Specifications

72 SAM0023-122898 ESS Technology, Inc.
ES1869 DATA SHEET
AUDIO MICROCONTROLLER COMMAND SUMMARY
AUDIO MICROCONTROLLER COMMAND SUMMARY
Table 26 Command Summary
Command
Data Byte(s)
Write/Read
Function
10h 1 write Direct write 8-bit DAC. Data is 8-bit unsigned format.
11h 2 writes Direct write 16-bit DAC. Data is 16-bit unsigned format, first low byte then high byte.
14h 2 writes Start Normal mode DMA for 8-bit DAC transfer. Data is transfer count - 1, least byte first. Stereo DAC
transfer if stereo flag is set in mixer register 0Eh. Maximum sample rate is 44 kHz mono, 22 kHz ste-
reo.
15h 2 writes Start Normal mode DMA for 16-bit DAC transfer. Data is transfer count - 1, least byte first. Stereo
DAC transfer if stereo flag is set in mixer register 0EH. Maximum sample rate is 22 kHz mono, 11 kHz
stereo.
1Ch Start Auto-Initialize mode DMA for 8-bit DAC transfer. Block size must be previously set by command
48h. Stereo DAC transfer if stereo flag is set in mixer register 0Eh. Maximum sample rate is 44 kHz
mono, 22 kHz stereo.
1Dh Start Auto-Initialize mode DMA for 16-bit DAC transfer. Block size must be previously set by com-
mand 48h. Stereo DAC transfer if stereo flag is set in mixer register 0Eh. Maximum sample rate is 22
kHz mono, 11 kHz stereo.
20h 1 read Direct mode 8-bit ADC. Data is 8-bit unsigned. Firmware controlled input volume for AGC.
21h 2 reads Direct mode 16-bit ADC, returns least byte first. Data is 16-bit unsigned format. Input volume con-
trolled by command DDh.
24h 2 writes Start Normal mode DMA for 8-bit ADC transfer. Data is transfer count - 1, least byte first. Firmware
controlled input volume for AGC. Maximum sample rate is 22 kHz: use command 99h for higher rates
up to 44 kHz.
25h 2 writes Start Normal mode DMA for 16-bit ADC transfer. Data is transfer count - 1, least byte first. Input vol-
ume controlled via command DDh. Maximum sample rate is 22 kHz.
2Ch Start Auto-Initialize mode DMA for 8 bit ADC transfer. Block size must be previously set by command
48h. Firmware controlled input volume for AGC. Maximum sample rate is 22 kHz: use command 98h
for higher rates up to 44 kHz.
2Dh Start Auto-Initialize mode DMA for 16-bit ADC transfer. Block size must be previously set by com-
mand 48h. Input volume is controlled by command DDh. Maximum sample rate is 22 kHz.
30h/31h MIDI input mode. Detects MIDI serial input data and transfers to data register, setting Data-Available
flag in register Audio_Base+Eh. Command 31h will also generate an interrupt request for each byte
received.
Exit MIDI input mode by executing a write to port Audio_Base+Ch. The data written is ignored. A soft-
ware reset will also exit this mode.
34h/35h MIDI UART mode. Acts like commands 30h/31h, except that any data written to Audio_Base+Ch will
be transmitted as MIDI serial output data. The only way to exit this mode is through software reset.
38h 1 write MIDI output. Transmit one byte.
40h 1 write Set time constant, X, for timer used for DMA mode DAC/ADC transfers: rate = 1 MHz / (256-X) X
must be less than or equal to 233. For stereo DAC, program sample rate for twice the per-channel
rate.
41h 1 write Alternate set time constant, X: rate = 1.5 MHz / (256-X)
This command provides more accurate timing for certain rates such as 22,050. X must be less than
equal to 222. For stereo DAC, program sample rate for twice the per-channel rate.
42h 1 write Set filter clock independently of timer rate. (note that the filter clock is automatically set by commands
40h/41h) Filter clock rate: rate = 7.16E6 / (256-X)
The relationship between the low-pass filter -3 dB point and the filter clock rate is approximately 1:82.
48h 2 writes Set block size-1 for high speed mode and auto-init mode transfer, least byte first.