Int 15/AH=01h

Amstrad PC1512 - WRITE DATA TO NON-VOLATILE RAM

AH = 01h
AL = NVRAM location (00h to 3Fh) (see #00405)
BL = NVRAM data value

Return:
AH = return code
00h OK
01h address bad
02h write error

See Also: AH=02h"Amstrad"

Format of Amstrad NVRAM: Offset Size Description (Table 00405)

00h BYTE time of day:
Seconds

01h BYTE alarm time:
Seconds

02h BYTE time of day:
Minutes

03h BYTE alarm time:
Minutes

04h BYTE time of day:
Hours

05h BYTE alarm time:
Hours 06h BYTE day of week, 1 = Sunday 07h BYTE day of month 08h BYTE month 09h BYTE year mod 100 0Ah BYTE RTC status register A (see #00406) 0Bh BYTE RTC status register B (see #00407) 0Ch BYTE RTC status register C (read-only) (see #00408) 0Dh BYTE RTC status register D

bit 7:
Battery good 0Eh 6 BYTEs time and date machine last used 14h BYTE user RAM checksum 15h WORD Enter key scancode/ASCII code 17h WORD Forward delete key scancode/ASCII code 19h WORD Joystick fire button 1 scancode/ASCII code 1Bh WORD Joystick fire button 2 scancode/ASCII code 1Dh WORD mouse button 1 scancode/ASCII code 1Fh WORD mouse button 2 scancode/ASCII code 21h BYTE mouse X scaling factor 22h BYTE mouse Y scaling factor 23h BYTE initial VDU mode and drive count 24h BYTE initial VDU character attribute 25h BYTE size of RAM disk in 2K blocks 26h BYTE initial system UART setup byte 27h BYTE initial external UART setup byte 28h 24 BYTEs available for user application

Note: Bytes 00h-0Dh are the same on the IBM AT as they are used/updated by the clock chip


Bitfields for RTC status register A:

Bit(s)  Description     (Table 00406)
7      set if date/time being updated
6-4    time base speed, default 010 = 32768 Hz
3-0    interrupt rate selection, default 0110 = 1024 Hz

See Also: #00405

Bitfields for RTC status register B: Bit(s) Description (Table 00407) 7 clear if normal update, set if abort update 6 periodic interrupt enable 5 alarm interrupt enable 4 update end interrupt enable 3 square wave enable 2 date mode (clear = BCD, set = binary) 1 24-hour format 0 daylight saving time enable

See Also: #00405


Bitfields for RTC status register C:

Bit(s)  Description     (Table 00408)
7      IRQF flag
6      PF flag
5      AF flag
4      UF flag

See Also: #00405

Category: Vendor-specific BIOS Extensions - Int 15h - A

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