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324 lines
9.7 KiB
324 lines
9.7 KiB
;
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;==================================================================================================
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; eZ80 UART DRIVER (SERIAL PORT)
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;==================================================================================================
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;
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;
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; Supported Line Characteristics are encoded as follows in the DE register pair:
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;
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; | **Bits** | **Characteristic** |
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; |---------:|----------------------------------------|
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; | 15-14 | Reserved (set to 0) |
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; | 13 | RTS (Not implemented) |
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; | 12-8 | Baud Rate* (see below) |
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; | 7 | DTR (Not implemented) |
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; | 6 | XON/XOFF Flow Control (not implemented)|
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; | 5 | Stick Parity (not implemented) |
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; | 4 | Even Parity (set for true) |
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; | 3 | Parity Enable (set for true) |
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; | 2 | Stop Bits (0-> 1 BIT, 1-> 2 BITS) |
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; | 1-0 | Data Bits (5-8 encoded as 0-3) |
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;
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; * The 5-bit Baud Rate value (V) is encoded as V = 75 * 2^X * 3^Y. The
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; bits are defined as YXXXX.
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;
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; STICK & EVEN & PARITY -> MARK PARITY -> NOT SUPPORTED
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; STICK & !EVEN & PARITY -> SPACE PARITY -> NOT SUPPORTED
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; THEREFORE, MARK PARITY WILL BE INTERPRETED AS EVEN PARITY
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; AND SPACE PARITY WILL BE INTERPRETED AS ODD PARITY
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UART0_LSR .EQU $C5
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UART0_THR .EQU $C0
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UART0_RBR .EQU $C0
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LSR_THRE .EQU $20
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LSR_DR .EQU $01
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EZUART_PREINIT:
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LD BC, EZUART_FNTBL
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LD DE, EZUART_CFG
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CALL CIO_ADDENT
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LD (EZUART_ID), A
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XOR A
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RET
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EZUART_INIT:
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CALL NEWLINE ; FORMATTING
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CALL PRTSTRD
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.TEXT "EZ80 UART: UART0$"
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XOR A
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RET
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;
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; ### Function 0x00 -- Character Input (CIOIN)
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;
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; Read and return a Character (E). If no character(s) are available in the
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; input buffer, this function will wait indefinitely. The returned Status
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; (A) is a standard HBIOS result code.
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;
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; Outputs:
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; E: Character
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; A: Status (0-OK, else error)
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;
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EZUART_IN:
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EZ80_UART_IN() ; CHAR RETURNED IN E
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RET
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;
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; ### Function 0x01 -- Character Output (CIOOUT)
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;
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; Send the Character (E). If there is no space available in the unit's output
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; buffer, the function will wait indefinitely. The returned Status (A) is a
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; standard HBIOS result code.
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;
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; Inputs:
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; E: Character
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;
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; Outputs:
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; A: Status (0-OK, else error)
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;
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EZUART_OUT:
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EZ80_UART_OUT()
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RET
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;
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; ### Function 0x02 -- Character Input Status (CIOIST)
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;
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; Return the count of Characters Pending (A) in the input buffer.
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;
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; The value returned in register A is used as both a Status (A) code and
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; the return value. Negative values (bit 7 set) indicate a standard HBIOS
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; result (error) code. Otherwise, the return value represents the number
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; of characters in the input buffer.
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;
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; Outputs:
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; A: Status / Characters Pending
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;
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EZUART_IST:
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EZ80_UART_IN_STAT()
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RET
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;
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; ### Function 0x03 -- Character Output Status (CIOOST)
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;
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; Return the status of the output FIFO. 0 means the output FIFO is full and
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; no more characters can be sent. 1 means the output FIFO is not full and at
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; least one character can be sent. Negative values (bit 7 set) indicate a
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; standard HBIOS result (error) code.
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;
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; Outputs
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; A: Status (0 -> Full, 1 -> OK to send, < 0 -> HBIOS error code)
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;
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EZUART_OST:
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EZ80_UART_OUT_STAT()
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RET
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BAUD_RATE .EQU 115200
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;
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; ### Function 0x04 -- Character I/O Initialization (CIOINIT)
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;
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; Apply the requested line Characteristics in (DE). The definition of the
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; line characteristics value is described above. If DE contains -1 (0xFFFF),
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; then the input and output buffers will be flushed and reset.
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; The Status (A) is a standard HBIOS result code.
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;
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; Inputs:
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; DE: Line Characteristics
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;
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; Outputs:
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; A: Status (0-OK, else error)
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;
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EZUART_INITDEV:
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LD A, D
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CP E
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JR NZ, NOT_RESET
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CP $FF
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JR NZ, NOT_RESET
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EZ80_UART_RESET()
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RET
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NOT_RESET:
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PUSH DE ; SAVE LINE CHARACTERISTICS
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LD A, D
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AND $1F ; ISOLATE ENCODED BAUD RATE
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LD L, A ; PUT IN L
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LD H, 0 ; H IS ALWAYS ZERO
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LD DE, 75 ; BAUD RATE DECODE CONSTANT
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CALL DECODE ; DE:HL := BAUD RATE
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EZ80_CPY_EHL_TO_UHL ; HL{23:0} <- E:HL{15:0}
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POP DE ; RESTORE REQUESTED LINE CHARACTERISTICS
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LD A, E
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AND 3 ; MASK FOR DATA BITS
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RLCA
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RLCA
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RLCA ; SHIFT TO BITS 4:3
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LD D, A ; SAVE INTO D
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BIT 2, E ; STOP BITS (1 OR 2)
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JR Z, ISKIP1
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SET 2, D ; APPLY TO D
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ISKIP1:
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BIT 3, E ; PARITY ENABLE
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JR Z, ISKIP2
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SET 1, D ; APPLY TO D
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ISKIP2:
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BIT 4, E ; EVEN PARITY
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JR Z, ISKIP3
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SET 0, D ; APPLY TO D
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ISKIP3:
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; D NOW CONTAINS THE LINE CONTROL BITS AS PER EZ80 FUNCTION
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EZ80_UART_CONFIG()
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RET
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#DEFINE TRANSLATE(nnn,rrr) \
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#defcont \ LDBCMM.LIL(nnn)
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#defcont \ SBCHLBC.LIL
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#defcont \ JR NC, $+7
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#defcont \ LD D, rrr
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#defcont \ JP uart_query_end
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;
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; ### Function 0x05 -- Character I/O Query (CIOQUERY)
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;
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; Returns the current Line Characteristics (DE). The definition of the line
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; characteristics value is described above. The returned status (A) is a
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; standard HBIOS result code.
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;
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; As the eZ80 UART driver supports more than the defined HBIOS baud rates, the
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; returned baud rate may be an approximation of the actual baud rate.
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;
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; Outputs:
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; DE: Line Characteristics
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; A: Status (0-OK, else error)
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;
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EZUART_QUERY:
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EZ80_UART_QUERY()
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; HL{23:0} := BAUD RATE
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; D = LINE CONTROL BITS
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PUSH DE ; SAVE D
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OR A
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; HL24 bit has the baud rate, we need to convert to the 5 bit representation?
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TRANSLATE(112, 00000b) ; BAUDRATE=75 (BETWEEN 0 AND 112)
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TRANSLATE(187-112, 00001b) ; BAUDRATE=150 (BETWEEN 113 AND 187)
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TRANSLATE(262-187, 10000b) ; BAUDRATE=225 (BETWEEN 188 AND 262)
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TRANSLATE(375-262, 00010b) ; BAUDRATE=300 (BETWEEN 263 AND 375)
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TRANSLATE(525-375, 10001b) ; BAUDRATE=450 (BETWEEN 376 AND 525)
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TRANSLATE(750-525, 00011b) ; BAUDRATE=600 (BETWEEN 526 AND 750)
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TRANSLATE(1050-750, 10010b) ; BAUDRATE=900 (BETWEEN 751 AND 1050)
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TRANSLATE(1500-1050, 00100b) ; BAUDRATE=1200 (BETWEEN 1051 AND 1500)
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TRANSLATE(2100-1500, 10011b) ; BAUDRATE=1800 (BETWEEN 1501 AND 2100)
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TRANSLATE(3000-2100, 00101b) ; BAUDRATE=2400 (BETWEEN 2101 AND 3000)
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TRANSLATE(4200-3000, 10100b) ; BAUDRATE=3600 (BETWEEN 3001 AND 4200)
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TRANSLATE(6000-4200, 00110b) ; BAUDRATE=4800 (BETWEEN 4201 AND 6000)
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TRANSLATE(8400-6000, 10101b) ; BAUDRATE=7200 (BETWEEN 6001 AND 8400)
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TRANSLATE(12000-8400, 00111b) ; BAUDRATE=9600 (BETWEEN 8401 AND 12000)
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TRANSLATE(16800-12000, 10110b) ; BAUDRATE=14400 (BETWEEN 12001 AND 16800)
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TRANSLATE(24000-16800, 01000b) ; BAUDRATE=19200 (BETWEEN 16801 AND 24000)
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TRANSLATE(33600-24000, 10111b) ; BAUDRATE=28800 (BETWEEN 24001 AND 33600)
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TRANSLATE(48000-33600, 01001b) ; BAUDRATE=38400 (BETWEEN 33601 AND 48000)
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TRANSLATE(67200-48000, 11000b) ; BAUDRATE=57600 (BETWEEN 48001 AND 67200)
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TRANSLATE(96000-67200, 01010b) ; BAUDRATE=76800 (BETWEEN 67201 AND 96000)
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TRANSLATE(134400-96000, 11001b) ; BAUDRATE=115200 (BETWEEN 96001 AND 134400)
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TRANSLATE(192000-134400, 01011b) ; BAUDRATE=153600 (BETWEEN 134401 AND 192000)
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TRANSLATE(268800-192000, 11010b) ; BAUDRATE=230400 (BETWEEN 192001 AND 268800)
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TRANSLATE(384000-268800, 01100b) ; BAUDRATE=307200 (BETWEEN 268801 AND 384000)
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TRANSLATE(537600-384000, 11011b) ; BAUDRATE=460800 (BETWEEN 384001 AND 537600)
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TRANSLATE(768000-537600, 01101b) ; BAUDRATE=614400 (BETWEEN 537601 AND 768000)
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TRANSLATE(1075200-768000, 11100b) ; BAUDRATE=921600 (BETWEEN 768001 AND 1075200)
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TRANSLATE(1536000-1075200, 01110b) ; BAUDRATE=1228800 (BETWEEN 1075201 AND 1536000)
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TRANSLATE(2150400-1536000, 11101b) ; BAUDRATE=1843200 (BETWEEN 1536001 AND 2150400)
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TRANSLATE(3072000-2150400, 01111b) ; BAUDRATE=2457600 (BETWEEN 2150401 AND 3072000)
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TRANSLATE(5529600-3072000, 11110b) ; BAUDRATE=3686400 (BETWEEN 3072001 AND 5529600)
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LD D, 11111b ; BAUDRATE=7372800 (>=5529601)
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uart_query_end:
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POP BC ; B = LINE CONTROL BITS
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; Convert from line control settings from:
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;
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; B{0:1} = Parity (00 -> NONE, 01 -> NONE, 10 -> ODD, 11 -> EVEN)
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; B{2} = Stop Bits (0 -> 1, 1 -> 2)
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; B{3:4} = Data Bits (00 -> 5, 01 -> 6, 10 -> 7, 11 -> 8)
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; B{5:5} = Hardware Flow Control CTS (0 -> OFF, 1 -> ON)
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;
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; to
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;
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; E{7} = TODO: DTR
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; E{6} = NOT IMPLEMENTED: XON/XOFF Flow Control
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; E{5} = NOT SUPPORTED: Stick Parity (set for true)
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; E{4} = Even Parity (set for true)
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; E{3} = Parity Enable (set for true)
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; E{2} = Stop Bits (set for true)
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; E{1:0} = Data Bits (5-8 encoded as 0-3)
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XOR A
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OR 3 << 3 ; ISOLATE DATA BITS
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AND B ; MASK IN DATA BITS
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RRCA ; SHIFT TO BITS 1:0
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RRCA
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RRCA
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LD H, A ; H{1:0} DATA BITS
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BIT 2, B ; STOP BITS
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JR Z, SKIP1
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SET 2, H ; APPLY TO H
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SKIP1:
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BIT 1, B ; PARITY ENABLE
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JR Z, SKIP2
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SET 3, H ; APPLY TO H
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SKIP2:
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BIT 0, B ; EVEN PARITY
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JR Z, SKIP3
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SET 4, H ; APPLY TO H
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SKIP3:
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LD E, H
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XOR A
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RET
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;
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; ### Function 0x06 -- Character I/O Device (CIODEVICE)
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;
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; Returns device information. The status (A) is a standard HBIOS result
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; code.
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;
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; Outputs
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; A: Status (0 - OK)
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; C: Device Attribute (0 - RS/232)
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; D: Device Type (CIODEV_EZ80UART)
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; E: Physical Device Number
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; H: Device Mode (0)
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; L: Device I/O Base Address - Not Supported (0)
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;
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EZUART_DEVICE:
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LD D, CIODEV_EZ80UART ; D := DEVICE TYPE
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LD E, (IY) ; E := PHYSICAL UNIT
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LD C, 0 ; C := DEVICE TYPE, 0x00 IS RS-232
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LD HL, 0 ; H := MODE, L := BASE I/O ADDRESS
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XOR A ; SIGNAL SUCCESS
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RET
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EZUART_CFG:
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EZUART_ID: .DB 0
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EZUART_FNTBL:
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.DW EZUART_IN
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.DW EZUART_OUT
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.DW EZUART_IST
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.DW EZUART_OST
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.DW EZUART_INITDEV
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.DW EZUART_QUERY
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.DW EZUART_DEVICE
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#IF (($ - EZUART_FNTBL) != (CIO_FNCNT * 2))
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.ECHO "*** INVALID EZUART FUNCTION TABLE ***\n"
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#ENDIF
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