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-rw-r--r--src/mame/machine/taitocchip.cpp22
1 files changed, 11 insertions, 11 deletions
diff --git a/src/mame/machine/taitocchip.cpp b/src/mame/machine/taitocchip.cpp
index be743a6cfff..dfd85aa29fa 100644
--- a/src/mame/machine/taitocchip.cpp
+++ b/src/mame/machine/taitocchip.cpp
@@ -64,18 +64,18 @@ CLK is supplied with a 12MHZ oscillator on operation wolf
(move below MODE notes to upd7811.cpp?)
The four Mode0/Mode1 combinations are:
- LOW/LOW 78c11 mem map is 4k external rom (i.e. the eprom inside the c-chip) from 0x0000-0x0FFF;
- the low 4 bits of port F are used, to provide the high 4 address bits.
- speculation: likely the eprom can be banked so the low or high half is visible here,
- or possibly one fixed window and 3 variable windows, managed by the asic?
- LOW/HIGH 78c11 mem map boots to internal rom (mask rom inside the 78c11 inside the c-chip) from
- 0x0000-0x0fff but the memory map is under full mcu control and can select any of the
- four modes (internal only, 4k external, 16k external, 64k external)
+ LOW/LOW 78c11 mem map is 4k external rom (i.e. the eprom inside the c-chip) from 0x0000-0x0FFF;
+ the low 4 bits of port F are used, to provide the high 4 address bits.
+ speculation: likely the eprom can be banked so the low or high half is visible here,
+ or possibly one fixed window and 3 variable windows, managed by the asic?
+ LOW/HIGH 78c11 mem map boots to internal rom (mask rom inside the 78c11 inside the c-chip) from
+ 0x0000-0x0fff but the memory map is under full mcu control and can select any of the
+ four modes (internal only, 4k external, 16k external, 64k external)
The following two modes are unusable on the c-chip:
- HIGH/LOW 78c11 mem map is 16k external rom from 0x0000-0x3FFF;
- the low 6 bits of port F are used, to provide the high 6 address bits.
- HIGH/HIGH 78c11 mem map is 64k external rom from 0x0000-0xFFFF;
- all 8 bits of port F are used to provide the high 8 address bits.
+ HIGH/LOW 78c11 mem map is 16k external rom from 0x0000-0x3FFF;
+ the low 6 bits of port F are used, to provide the high 6 address bits.
+ HIGH/HIGH 78c11 mem map is 64k external rom from 0x0000-0xFFFF;
+ all 8 bits of port F are used to provide the high 8 address bits.
VPP is only used for programming the 27c64, do not tie it to 18v or you will probably overwrite the 27c64 with garbage.
(see http://www.cpcwiki.eu/index.php/UPD7810/uPD7811 )