SPRUHM8K December 2013 – May 2024 TMS320F28374D , TMS320F28375D , TMS320F28376D , TMS320F28377D , TMS320F28377D-EP , TMS320F28377D-Q1 , TMS320F28378D , TMS320F28379D , TMS320F28379D-Q1
Table 21-63 shows which register bits enable the Transmit Frame-Synchronization Mode.
Register | Bit | Name | Function | Type | Reset Value | |
---|---|---|---|---|---|---|
PCR | 11 | FSXM | Transmit frame-synchronization mode | R/W | 0 | |
FSXM = 0 | Transmit frame synchronization is supplied by an external source via the FSX pin. | |||||
FSXM = 1 | Transmit frame synchronization is supplied by the McBSP, as determined by the FSGM bit of SRGR2. | |||||
SRGR2 | 12 | FSGM | Sample rate generator transmit frame-synchronization mode | R/W | 0 | |
Used when FSXM = 1 in PCR. | ||||||
FSGM = 0 | The McBSP generates a transmit frame-synchronization pulse when the content of DXR[1,2] is copied to XSR[1,2]. | |||||
FSGM = 1 | The transmitter uses frame-synchronization pulses generated by the sample rate generator. Program the FWID bits to set the width of each pulse. Program the FPER bits to set the frame-synchronization period. |
Table 21-64 shows how FSXM and FSGM select the source of transmit frame-synchronization pulses. The three choices are:
Table 21-64 also shows the effect of each bit setting on the FSX pin. The polarity of the signal on the FSX pin is determined by the FSXP bit.
FSXM | FSGM | Source of Transmit Frame Synchronization | FSX Pin Status |
---|---|---|---|
0 | 0 or 1 | An external frame-synchronization signal enters the McBSP through the FSX pin. The signal is then inverted by FSXP before being used as internal FSX. | Input |
1 | 1 | Internal FSX is driven by the sample rate generator frame-synchronization signal (FSG). | Output. FSG is inverted by FSXP before being driven out on FSX pin. |
1 | 0 | A DXR-to-XSR copy causes the McBSP to generate a transmit frame-synchronization pulse that is 1 cycle wide. | Output. The generated frame-synchronization pulse is inverted as determined by FSXP before being driven out on FSX pin. |