Registers; Register 231H - Miscellaneous Control; Register 233H - Flash Bios Control - Xycom AHIP-370 Manual

AHIP-370 Manual

Registers

The AHIP-370 contains five I/O ports: 231h, 233h, 234h, and a user-definable port
(port 180/1h, 2E0/1h, 3E0/1h, or 300/1h). These ports are compatible with AHIP4+
and AHIP 6+.
Register 231h – Miscellaneous Control
Register 231h controls the LEDs and signals shown in the following table.
Bit
0
1
2
3
4
5*
6
7
*Note:
AT bus. This bit also enables the FLASH @C0000h when booting to FLASH.
Register 233h – Flash BIOS Control
Register 233h controls the signals shown in the following table.
Bit
0
1
2
3
4
5
6
7
20
Table 2- 7. Register 231h - CPU LED Port
LED/Signal Result
Reserved 0
DOC 2000 1= Enables DOC 2000
Reserved 0
Reserved 0
Reserved 0
ENFLASHWR 1 = Enables Flash write
VGA_EN 1 = Enables on-board VGA
CLRCMS 1 = CMOS okay
0 = Clear CMOS
This bit must be 1 to make FLASH visible @D0000h when booting from
Table 2- 8. Register 233h - Flash BIOS Control Register
Signal Result
FLA15 Flash address 15 - page control bit
FLA16 Flash address 16- page control bit
FLA17 Flash address 17 - page control bit
FLA18 Flash address 18 - page control bit
FPSEL0 Flat panel select bit 0
FPSEL1 Flat panel select bit 1
FPSEL2 Flat panel select bit 2
FPSEL3 Flat panel select bit 3
R/W
R
R/W
R
R
R
R/W
R
R
R/W
R/W
R/W
R/W
R/W
R
R
R
R