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This version (18 May 2011 15:55) was approved by jeanmca.The Previously approved version (18 May 2011 15:42) is available.Diff

SPORT: Synchronous Serial Peripheral Port

Sport interface supports a variety of serial data communication protocols. Key features and capability of SPORT interface are

  • Continuously running clock
  • Serial data words from 3 to 32 bits in lengths, either MSB or LSB first
  • Two synchronous transmit and two synchronous receive data signals and buffers to double the total supported data stream
  • Configurable frame synchronisation signals

SPORT TSCLK =SCLK/(2 x(SPORT TCLKDIV+1))

SCLK = 120MHz
SPORT_TCLKDIV = 0 to 65535

TSCLK Max = ((120M)/ (2 x(1+1)))=60MHz
TSCLK Min = ((120M)/(2 x(65535+1))) ≈ 915.52Hz
Other allowable values : 60MHz, 30MHz, 20MHz, 12MHz, 10MHz, 7.5MHz, 6MHz
NOTE : The value of Transmit Frame Sync Frequency is a function of the clock frequency of the transmit clock. SPORT_TFSDIV is the number of serial clock cycles between frame sync assertions.

SPORT TFS = (TSCLK / SPORT TFSDIV +1)

SPORT_TFSDIV must be greater than the serial word length -1. This ensures that the the frame sync is deasserted prior to reassertion for the the framed word. Therefore depending on the word size chosen for data transmission and the clock frequency selected the Frame Sync freqency will vary. Taking a 60MHz TSCLK and a serial wordlenght of 32. The minimum and maximum SPORT TFS are calculated as follows
SPORT TFS Max = ((60M)/(32 +1)) ≈ 1800000 Hz
SPORT TFS Min = ((60M)/(65536 +1)) ≈ 1000Hz The Receive Clock freqency and the Receive Frame Rates available can be calculated similarily to the TSCLK and the TFS rates
SPORT RSCLK = (SCLK/(2 x(SPORT_RCLKDIV+1)))
SCLK = 120MHz
SPORT_RCLKDIV = 0 to 65535
RSCLK Max = 60MHz, RSCLK MIN ≈ 915.52Hz
SPORT RFS = (RSCLK/(SPORT RFSDIV +1))

Pin Blackfin Name Pin 120 Pin Connector Name Description
DTxPRISPORT_DT0Transmit Data Primary
DTxSECSPORT_DT1Transmit Data Secondary
TSCLKxSPORT_TSCLKTransmit Clock
TFSxSPORT_TFSTransmit Frame Sync
DRxPRISPORT_DR0Receive Data Primary
DRxSECSPORT_DR1Receive Data Secondary
RSCLKxSPORT_RSCLKReceive Clock
TRSxSPORT_RFSReceive Frame Sync

Table 1: SPORT Pin Assignments

There are two transmit and two receive channels in the SPORT interface. By default the primary transmit and receive channels, DT0 and DR0, are enabled and the secondary transmit and receive channels, DT1 and DR1, are disabled. To enable the secondary transmit and receive channels, set the secEnable property in the SPORT object to true and wire the second transmit and receive lines to DT1 and DR1. The max clock frequency which can be used in this case is now halved, so 30MHz SPORT TSCLK and RSCLK. The data sent down to the SDP should be interleaved, the every second location containing data for DT0 and DT1 respectively. Below is a timing example showing the transmit clock, frame sync and data lines with SecEnable set to true.
To achieve the example below the array transmitted over the SPORT interface is

IndexElementChannel
00x49DT0
10x96DT1
20x31DT0
30xC6DT1

Similarly data read from the SDP SPORT Interface in secEnable mode must be de-interleaved in the top level application to separate the data into data from DR0 and DR1.

Understanding the Frame Sync Signal


An Early Frame Sync Signal will be active for one clock pulse, and then become deactivate. Once the signal has been deactivated, valid data will be available.
A Late Frame Sync Signal frames the valid data, so is active for the length of time that valid data is available and is deactivated once the word to be transmitted or received has been fully sent.


Figure 1 : SPORT Frame Sync Signals


Receive Data


Figure 2 : SPORT_DR0/SPORT_DR1 & early frame sync


Figure 3 : SPORT_DR0/SPORT_DR1 & late frame sync


Transmit Data


Figure 4 : SPORT_DT0/SPORT_DT1 & late frame sync

There are two SPORT Controllers on the Blackfin BF527 and these are exposed through the two connectors on the SDP-B.
SPORT0 is on Connector A of the SDP, SPORT1 is on Connector B of the SDP.
The SPORT Interface Pins are 3.3V tolerant only.

resources/eval/sdp/sdp-b/peripherals/sport.txt · Last modified: 18 May 2011 15:55 by jeanmca