Specifications

44 SAM0025A-062397 ESS Technology, Inc.
ES1879 DATA SHEET
I/O PORTS
PRELIMINARY
Power Management Register (Audio_Base+7h, R/W)
Reading or writing port Audio_Base+7h does not
automatically wake up the ES1879.
Bit Definitions:
Read Data Register (Audio_Base+Ah, R)
Reads data from embedded audio microcontroller. Poll bit
7 of port Audio_Base+Eh to test whether the register
contents are valid.
Write Data Register (Audio_Base+Ch, W)
Writes data to embedded audio microcontroller. Sets bit 7
of port Audio_Base+Ch high (write buffer not available)
until data is processed by the ES1879.
Read Data Register (Audio_Base+Ch, R)
Bit Definitions:
Read Buffer Status Register (Audio_Base+Eh, R)
A read from port Audio_Base+Eh will reset any interrupt
request.
Bit Definitions:
Programmed I/O Access to FIFO Register
(Audio_Base+Fh, R/W)
This port can be used to replace Extended mode DMA
with Programmed I/O.
Suspend
request
0
FM
synth
reset
0
7654321 0
Bits Name Description
7 Suspend
request
Pulse high, then low to request suspend.
6 – Reserved. Always write 0.
5 FM synth
reset
1 = Hold FM synthesizer in reset.
0 = Release FM synthesizer from reset.
4:0 – Reserved. Always write 0.
D7 D6 D5 D4 D3 D2 D1 D0
76543210
D7 D6 D5 D4 D3 D2 D1 D0
76543210
D7 D6 D5 D4 D3 D2 D1 D0
76543210
Bits Name Description
7 Busy flag 1 = write buffer not available or ES1879 busy.
0 = write buffer available or ES1879 not busy.
6 1 = Data available in read buffer.
0 = Data not available in read buffer.
This flag is reset by a read from port
Audio_Base+Ah.
5 1 = Extended mode FIFO Full (256 bytes
loaded).
4 1 = Extended mode FIFO Empty (0 bytes
loaded).
3 1 = FIFO Half Empty, Extended mode flag.
2 1 = ES1879 microcontroller generated an inter-
rupt request (e.g., from Compatibility mode
DMA complete).
1 1 = Interrupt request generated by FIFO Half
Empty flag change. Used by Programmed I/O
interface to FIFO in Extended mode.
0 1 = Interrupt request generated by DMA
counter overflow in Extended mode.
D7 D6 D5 D4 D3 D2 D1 D0
76543210
Bits Name Description
7 1 = Data available in read buffer.
0 = Data not available in read buffer.
This flag is reset by a read from port
Audio_Base+Ah.
D7 D6 D5 D4 D3 D2 D1 D0
76543210