National CP3BT26 - Manual (Page 151)

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CP3
BT26
20.6.6 Freeze Mode
The audio interface provides a FREEZE input, which allows
to freeze the status of the audio interface while a develop-
ment system examines the contents of the FIFOs and reg-
isters.
When the FREEZE input is asserted, the audio interface be-
haves as follows:
„ The receive FIFO or receive DMA registers are not up-
dated with new data.
„ The receive status bits (RXO, RXE, RXF, and RXAF) are
not changed, even though the receive FIFO or receive
DMA registers are read.
„ The transmit shift register (ATSR) is not updated with
new data from the transmit FIFO or transmit DMA regis-
ters.
„ The transmit status bits (TXU, TXF, TXE, and TXAE) are
not changed, even though the transmit FIFO or transmit
DMA registers are written.
The time at which these registers are frozen will vary be-
cause they operate from a different clock than the one used
to generate the freeze signal.
20.7 AUDIO INTERFACE REGISTERS
Table 67 Audio Interface Registers
Name Address Description
ARFR FF FD40h
Audio Receive FIFO
Register
ARDR0 FF FD42h
Audio Receive DMA
Register 0
ARDR1 FF FD44h
Audio Receive DMA
Register 1
ARDR2 FF FD46h
Audio Receive DMA
Register 2
ARDR3 FF FD48h
Audio Receive DMA
Register 3
ATFR FF FD4Ah
Audio Transmit FIFO
Register
ATDR0 FF FD4Ch
Audio Transmit DMA
Register 0
ATDR1 FF FD4Eh
Audio Transmit DMA
Register 1
ATDR2 FF FD50h
Audio Transmit DMA
Register 2
ATDR3 FF FD52h
Audio Transmit DMA
Register 3
AGCR FF FD54h
Audio Global
Configuration Register
AISCR FF FD56h
Audio Interrupt Status
and Control Register
ARSCR FF FD58h
Audio Receive Status
and Control Register
ATSCR FF FD5Ah
Audio Transmit Status
and Control Register
ACCR FF FD5Ch
Audio Clock Control
Register
ADMACR FF FD5Eh
Audio DMA Control
Register