MSB900/L Detailed Technical Manual V1.0 |
5.9.2.System I/O map
The following table details the legacy I/O range for 000h through 4FFh. Each I/O location has a read/write (R/W) capability.
Note the following abbreviations:
---Unknown or can not be determined.
Yes | Read and write the register at the indicated location. No shadow required. | |
WO | Write only. Value written can not be read back. Reads do not contain any useful information. | |
RO | Read only. Writes have no effect. | |
Shw | The value written to the register can not be read back via the same I/O location. Read back is | |
accomplished via a “Shadow” register located in MSR space. | ||
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Shw@ | Reads of the location return a constant or meaningless value. | |
Shw$ | Reads of the location return a status or some other meaningful information | |
Rec | Writes to the location are “recorded” and written to the LPC. Reads to the location return the re- | |
corded value. The LPC is not read. | ||
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I/O Map
I/O Addr. | Function | Size | R/W | Comment |
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000h | Slave DMA Address - Channel 0 | 8bit | Yes | 16bit values in two transfers. |
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001h | Slave DMA Counter - Channel 0 | 8bit | Yes | 16bit values in two transfers. |
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002h | Slave DMA Address - Channel 1 | 8bit | Yes | 16bit values in two transfers. |
003h | Slave DMA Counter - Channel 1 | 8bit | Yes | 16bit values in two transfers. |
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004h | Slave DMA Address - Channel 2 | 8bit | Yes | 16bit values in two transfers. |
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005h | Slave DMA Counter - Channel 2 | 8bit | Yes | 16bit values in two transfers. |
006h | Slave DMA Address - Channel 3 | 8bit | Yes | 16bit values in two transfers. |
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007h | Slave DMA Counter - Channel 3 | 8bit | Yes | 16bit values in two transfers. |
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008h | Slave DMA Command/Status - Channels [3:0] | 8bit | Shw$ |
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009h | Slave DMA Request - Channels [3:0] | 8bit | WO | Reads return value B2h. |
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00Ah | Slave DMA Mask - Channels [3:0] | 8bit | Shw@ | Reads return value B2h. |
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00Bh | Slave DMA Mode - Channels [3:0] | 8bit | Shw@ | Reads return value B2h. |
00Ch | Slave DMA Clear Pointer - Channels [3:0] | 8bit | WO | Reads return value B2h. |
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00Dh | Slave DMA Reset - Channels [3:0] | 8bit | WO | Reads return value B2h. |
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00Eh | Slave DMA Reset Mask - Channels [3:0] | 8bit | Shw@ | Reads return value B2h. |
00Fh | Slave DMA General Mask - Channels [3:0] | 8bit | Shw@ | Reads return value B2h. |
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No Specific Usage |
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020h | PIC Master - Command/Status | 8bit | Shw$ |
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021h | PIC Master - Command/Status | 8bit | Shw$ |
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No Specific Usage |
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040h | PIT – System Timer | 8bit | Shw$ |
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041h | PIT – Refresh Timer | 8bit | Shw$ |
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042h | PIT – Speaker Timer | 8bit | Shw$ |
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043h | PIT – Control | 8bit | Shw$ |
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No Specific Usage |
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Continued… |
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