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@ -659,7 +659,7 @@ |
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<p><strong>RomWBW System Guide</strong> \ |
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Version 3.6 \ |
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Wayne Warthen (<a href="mailto:wwarthen@gmail.com">wwarthen@gmail.com</a>) \ |
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20 Aug 2025</p> |
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23 Aug 2025</p> |
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<h1 id="overview">Overview</h1> |
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<p>The objective of RomWBW is to provide firmware, operating systems, and |
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applications targeting the Z80 family of CPUs. The firmware, in the form |
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@ -1389,9 +1389,10 @@ latter version of the SBC.</p> |
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<p>On systems with RTC devices (that have Non-Volatile RAM), RomWBW |
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supports storing some limited configuration option options inside this |
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RAM.</p> |
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<p>Several configuration options are currently supported; these are known |
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as Switches. The following switch ID’s are defined, and described in |
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sections below.</p> |
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<p>Several configuration options are currently supported; these are |
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referred to as Switches. In this case the term Switches refers to “soft” |
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switches stored in NVRAM, not physical panel switches. The following |
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switch ID’s are defined, and described in sections below.</p> |
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<table> |
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<thead> |
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<tr> |
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@ -1464,6 +1465,12 @@ using the configuration.</p> |
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</table> |
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<p>The above data is copied into the HBIOS Configuration Block (HCB) at |
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startup at the location starting at CB_SWITCHES.</p> |
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<p>Although the switch data is stored in NVRAM, it is intended that you use |
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<a href="#sysget-subfunction-0xc0-get-switches-switch">SYSGET Subfunction 0xC0 – Get Switches |
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(SWITCH)</a> or <a href="#sysset-subfunction-0xc0-set-switches-switch">SYSSET |
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Subfunction 0xC0 – Set Switches |
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(SWITCH)</a> to read or write |
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the switch values described here.</p> |
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<h3 id="boot-options-nvsw_bootopts">Boot Options (NVSW_BOOTOPTS)</h3> |
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<p>16 bit Switch defining the ROM application or Disk device to boot if |
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automatic booting is enabled.</p> |
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@ -1521,13 +1528,13 @@ automatic booting is enabled.</p> |
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</tbody> |
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</table> |
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<h3 id="status-reset-0xff">Status Reset (0xFF)</h3> |
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<p>The Status Reset switch is not a general purpose switch, it is a control |
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mechanism to allow the global status of all switches to be determined. |
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The meaning of the switch is different for Read (Get Status) and Write |
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(Reset NVRAM)</p> |
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<p>The Status Reset switch is a virtual switch that does not have a |
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corresponding stored value. It is a control mechanism to allow the |
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global status of all switches to be determined. The meaning of the |
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switch is different for Read (Get Status) and Write (Reset NVRAM)</p> |
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<h4 id="get-get-status">GET (Get Status)</h4> |
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<p>The read Get Status of switches. This returns very specific values from |
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the function call.</p> |
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<p>When the switch number 0xFF is read (using the Get Switches function), |
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the status of the NVRAM switches will be returned as follows:</p> |
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<table> |
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<thead> |
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<tr> |
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@ -1555,8 +1562,10 @@ the function call.</p> |
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</tbody> |
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</table> |
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<h4 id="set-reset-nvram">SET (Reset NVRAM)</h4> |
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<p>Reset NVRAM to default values. This will wipe any existing data and set |
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default values into NVRAM.</p> |
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<p>When the switch number 0xFF is written (using the Set Switches |
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function), the stored values of all switches will be reset to their |
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default values. This will wipe any existing data and set default values |
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into NVRAM.</p> |
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<h1 id="driver-model">Driver Model</h1> |
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<p>The framework code for bank switching also allows hardware drivers to be |
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implemented mostly without concern for memory management. Drivers are |
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@ -3149,11 +3158,10 @@ result code.</p> |
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</table> |
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<p>Returns device information for the RTC unit. The Status (A) is a |
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standard HBIOS result code.</p> |
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<p>Device Attribute (C) values are not yet defined. Device Type (D) |
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indicates the specific hardware driver that handles the specified |
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character unit. Values are listed at the start of this section. Device |
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Number (E) indicates the physical device number assigned per driver |
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which is always 0 for RTC.</p> |
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<p>Device Attributes (C) values are not yet defined. Device Type (D) |
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indicates the specific hardware driver that handles the RTC unit. Values |
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are listed at the start of this section. Device Number (E) indicates the |
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physical device number assigned per driver which is always 0 for RTC.</p> |
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<p>Device Mode (H) is used to indicate the variant of the chip or circuit |
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that is used by the specified unit. The Device I/O Base Address (L) |
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indicates the starting port address of the hardware interface that is |
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wwarthen
5 months ago