
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
CLK
Frame
sync
Frame sync:
(0 bit delay)
Frame sync:
(1 bit delay)
Frame sync:
(2 bit delay)
Slot 0
Slot 1
Slot 0
Slot 1
Slot 0
Slot 1
Preliminary
www.ti.com
Architecture
10.2.6 Transfer Modes
10.2.6.1 Burst Transfer Mode
The McASP supports a burst transfer mode, which is useful for nonaudio data such as passing control
information between two processors. Burst transfer mode uses a synchronous serial format similar to
the TDM mode. The frame sync generation is not periodic or time-driven as in TDM mode, but data
driven, and the frame sync is generated for each data word transferred.
When operating in burst frame sync mode (
), as specified for transmit (XMOD = 0 in
AFSXCTL) and receive (RMOD = 0 in AFSRCTL), one slot is shifted for each active edge of the frame
sync signal that is recognized. Additional clocks after the slot and before the next frame sync edge are
ignored.
In burst frame sync mode, the frame sync delay may be specified as 0, 1, or 2 serial clock cycles. This
is the delay between the frame sync active edge and the start of the slot. The frame sync signal lasts
for a single bit clock duration (FRWID = 0 in AFSRCTL, FXWID = 0 in AFSXCTL).
For transmit, when generating the transmit frame sync internally, the frame sync begins when the
previous transmission has completed and when all the XBUF[n] (for every serializer set to operate as a
transmitter) has been updated with new data.
For receive, when generating the receive frame sync internally, frame sync begins when the previous
transmission has completed and when all the RBUF[n] (for every serializer set to operate as a receiver)
has been read.
Figure 10-19. Burst Frame Sync Mode
The control registers must be configured as follows for the burst transfer mode. The burst mode specific
bit fields are in bold face:
•
PFUNC: The clock, frame, data pins must be configured for McASP function.
•
PDIR: The clock, frame, data pins must be configured to the direction desired.
•
PDOUT, PDIN, PDSET, PDCLR: Not applicable. Leave at default.
•
GBLCTL: Follow the initialization sequence in
to configure this register.
•
AMUTE: Not applicable. Leave at default.
•
DLBCTL: If loopback mode is desired, configure this register according to
otherwise leave this register at default.
•
DITCTL: DITEN must be left at default 0 to select non-DIT mode. Leave the register at default.
•
RMASK/XMASK: Mask desired bits according to
and
•
RFMT/XFMT: Program all fields according to data format desired. See
•
AFSRCTL/AFSXCTL: Clear RMOD/XMOD bits to 0 to indicate burst mode. Clear FRWID/FXWID
bits to 0 for single bit frame sync duration. Configure other fields as desired.
•
ACLKRCTL/ACLKXCTL: Program all fields according to bit clock desired. See
•
AHCLKRCTL/AHCLKXCTL: Program all fields according to high-frequency clock desired. See
•
RTDM/XTDM: Program RTDMS0/XTDMS0 to 1 to indicate one active slot only. Leave other fields at
default.
1029
SPRUGX9 – 15 April 2011
Multichannel Audio Serial Port (McASP)
© 2011, Texas Instruments Incorporated
Содержание TMS320C6A816 Series
Страница 2: ...Preliminary 2 SPRUGX9 15 April 2011 Submit Documentation Feedback 2011 Texas Instruments Incorporated...
Страница 92: ...92 Read This First SPRUGX9 15 April 2011 Submit Documentation Feedback 2011 Texas Instruments Incorporated...
Страница 1122: ...1122 Multichannel Audio Serial Port McASP SPRUGX9 15 April 2011 Submit Documentation Feedback 2011 Texas Instruments Incorporated...
Страница 1562: ...1562 Real Time Clock RTC SPRUGX9 15 April 2011 Submit Documentation Feedback 2011 Texas Instruments Incorporated...
Страница 1658: ...1658 Timers SPRUGX9 15 April 2011 Submit Documentation Feedback 2011 Texas Instruments Incorporated...
Страница 1750: ...1750 UART IrDA CIR Module SPRUGX9 15 April 2011 Submit Documentation Feedback 2011 Texas Instruments Incorporated...
Страница 1984: ...1984 Universal Serial Bus USB SPRUGX9 15 April 2011 Submit Documentation Feedback 2011 Texas Instruments Incorporated...