Setting the SRG Frame-Sync Period and Pulse Width
Receiver Configuration
7-30
SPRU592E
7.18.1 About the Frame-Sync Period and the Frame-Sync Pulse Width
The sample rate generator can produce a clock signal, CLKG, and a
frame-sync signal, FSG. If the sample rate generator is supplying receive or
transmit frame synchronization, you must program the bit fields FPER and
FWID.
On FSG, the period from the start of a frame-sync pulse to the start of the next
pulse is (FPER + 1) CLKG cycles. The 12 bits of FPER allow a frame-sync
period of 1 to 4096 CLKG cycles, which allows up to 4096 data bits per frame.
When GSYNC = 1, FPER is a don’t care value.
Each pulse on FSG has a width of (FWID + 1) CLKG cycles. The eight bits of
FWID allow a pulse width of 1 to 256 CLKG cycles. It is recommended that
FWID be programmed to a value less than the programmed word length.
The values in FPER and FWID are loaded into separate down-counters. The
12-bit FPER counter counts down the generated clock cycles from the
programmed value (4095 maximum) to 0. The 8-bit FWID counter counts
down from the programmed value (255 maximum) to 0.
20 shows a frame-sync period of 16 CLKG periods
(FPER = 15 or 00001111b) and a frame-sync pulse with an active width of 2
CLKG periods (FWID = 1).
Figure 7
−
20. Frame of Period 16 CLKG Periods and Active Width of 2 CLKG Periods
FSG
CLKG
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
Frame-sync period: (FPER+1) x CLKG
Frame-sync pulse width: (FWID + 1) x CLKG
When the sample rate generator comes out of reset, FSG is in its inactive state.
Then, when FRST = 1 and FSGM = 1, a frame-sync pulse is generated. The
frame width value (FWID + 1) is counted down on every CLKG cycle until it
reaches 0, at which time FSG goes low. At the same time, the frame period
value (FPER + 1) is also counting down. When this value reaches 0, FSG goes
high, indicating a new frame.
Содержание TMS320VC5509
Страница 5: ...vi This page is intentionally left blank ...
Страница 43: ...McBSP Operation 2 20 SPRU592E This page is intentionally left blank ...
Страница 105: ...SPI Operation Using the Clock Stop Mode 6 16 SPRU592E This page is intentionally left blank ...
Страница 187: ...Transmitter Configuration 8 40 SPRU592E This page is intentionally left blank ...
Страница 191: ...General Purpose I O on the McBSP Pins 9 4 SPRU592E This page is intentionally left blank ...
Страница 201: ...Emulation Power and Reset Considerations 10 10 SPRU592E ...
Страница 207: ...Data Packing Examples 11 6 SPRU592E This page is intentionally left blank ...
Страница 273: ...McBSP Register Worksheet 13 14 SPRU592E This page is intentionally left blank ...