![Texas Instruments AM1808 Technical Reference Manual Download Page 1137](http://html.mh-extra.com/html/texas-instruments/am1808/am1808_technical-reference-manual_10945581137.webp)
Registers
1137
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Multichannel Audio Serial Port (McASP)
(1)
RBUF and XBUF are at the same address location. Reads access RBUF and writes access XBUF.
Table 24-8. McASP Registers Accessed by CPU/EDMA Through DMA Port
Offset
(1)
Access
Acronym
Register Description
2000h
Read Accesses
RBUF
Receive buffer DMA port address. Cycles through receive serializers, skipping over
transmit serializers and inactive serializers. Starts at the lowest serializer at the
beginning of each time slot. Reads from XRBUF[n] by way of RBUF by the
CPU/EDMA can only occur through the DMA port when RBUSEL = 0 in RFMT.
2000h
Write Accesses
XBUF
Transmit buffer DMA port address. Cycles through transmit serializers, skipping over
receive and inactive serializers. Starts at the lowest serializer at the beginning of each
time slot. Writes to XRBUF[n] by way of XBUF by the CPU/EDMA can only occur
through the DMA port when XBUSEL = 0 in XFMT.
(1)
The AFIFO cannot be used with the peripheral configuration port. Only the DMA port has access to the AFIFO.
Table 24-9. McASP AFIFO Registers Accessed Through Peripheral Configuration Port
(1)
Offset
Acronym
Register Description
Section
1000h
AFIFOREV
AFIFO revision identification register
1010h
WFIFOCTL
Write FIFO control register
1014h
WFIFOSTS
Write FIFO status register
1018h
RFIFOCTL
Read FIFO control register
101Ch
RFIFOSTS
Read FIFO status register
24.1.1 Register Bit Restrictions
Some bit fields (see
Bits With Restrictions on When They May be Changed
) have restrictions on when
they may be changed. These restrictions take the form of certain registers that must be asserted in
GBLCTL. Once these registers have been asserted, the user may then, and only then, change the desired
bit field.
Bits With Restrictions on When They May be Changed
To Change
Register:
To Change
Bit Field:
... these registers must be asserted in GBLCTL
HCLKRRST
RGRST
RSRCLR
RSMRST
RFRST
HCLKXRST
XGRST
XSRCLR
XSMRST
XFRST
DITCTL
DITEN
x
x
XFMT
XSSZ
x
XFMT
XDATDLY
x
x
RFMT
RSSZ
x
RFMT
RDATDLY
x
AFSXCTL
FSXP
x
x
AFSXCTL
FSXM
x
x
AFSXCTL
FXWID
x
x
AFSXCTL
XMOD
x
x
AFSRCTL
FSRP
x
x
AFSRCTL
FSRM
x
x
AFSRCTL
FRWID
x
x
AFSRCTL
RMOD
x
x
ACLKXCTL
CLKXDIV
x
x
x
x
ACLKXCTL
CLKXM
x
x
x
ACLKXCTL
ASYNC
x
x
ACLKXCTL
CLKXP
x
x
x
ACLKRCTL
CLKRDIV
x
x
x
x
ACLKRCTL
CLKRM
x
x
x
ACLKRCTL
CLKRP
x
x
x