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8XC196KR/NT: Synchronous Serial I/O (SSIO) Port Timings

We currently do not have specifications for the SSIO in our datasheets, therefore this is to be used as a guide when utilizing the SSIO peripheral. The timings listed in Table 1 were obtained by lab analysis or by analysis of design. These timings are not tested in production, therefore are not guaranteed. The timings shown are based on the SSIO_BAUD register being equal to 80h, which is the fastest operation of the SSIO, and FFh, which is the slowest. For example, the KR at 16MHz will yield baudrates from 2MHz (80h) to 15.625KHz (FFh).

For more information on the SSIO, refer to the 8XC196KX User's Manual or the 8XC196NT User's Manual.

Table 1: SSIO Port Timings.
SymbolParameterBRR=80HBRR=FFhUnits
TCLCLClock Period for SCn8 Tosc1024 Toscns
TCLCHClock Falling Edge to Clock Rising Edge4 Tosc512 Toscns
TDVCHInput Data Setup to Clock Rising Edge10 (min)ns
TCHDXInput Data Hold after Clock Rising Edge2 Tosc + 40 (min)ns
TCLDVClock Falling Edge to Data Out Valid3 Tosc + 40 (max)ns

Note: The timings presented above are not tested nor guaranteed. They were obtained by lab analysis at room temperature or by analysis of design.

Signals: Conditions:
C = Clock L = Low
D = Data H = High
V = Valid
X = No longer valid

Figure 1: Waveform Diagrams


Table 2 lists sample code that uses SSIO channel 0 to continuously send data (AAh) to be received by SSIO channel 1. This is called `loop back mode', when both channels are connected together (ie- SC0 (master) connected to SC1 (slave) and SD0 (master) connected to SD1 (slave)). The code can be modified to send only one byte of data by clearing bit 2 (ATR) in the SSIOx_CON register.


Table 2: SSIO code which continuously transmits data from SD0 to SD1.
WSR EQU 014H:BYTE
SP_CON EQU 011H:BYTE
BAUD_RATE EQU 00EH:BYTE
P6_REG EQU 0D5H:BYTE
P6_DIR EQU 0D3H:BYTE
P6_MODE EQU 0D1H:BYTE
SSIO_BAUD EQU 0B4H:BYTE
SSIO0_CON EQU 0B1H:BYTE
SSIO1_CON EQU 0B3H:BYTE
SSIO0_BUF EQU 0B0H:BYTE
SSIO1_BUF EQU 0B2H:BYTE
RESULT EQU 122H:BYTE
 
CSEG AT 2080H
LDB WSR,#1FH ;window 1F
LDB P6_REG,#0C0H ;set ch1, clr ch0
LDB P6_DIR,#0C0H ;ch1=p/p, ch0=in
LDB P6_MODE,#0F0H ;special function
LDB SSIO_BAUD,#80H ;2M baud
LDB SSIO0_CON,#0CDH ;master_xmit
LDB SSIO1_CON,#0CH ;slave_receive
HERE: 
LDB SSIO0_BUF,#0AAH ;xmit data `AA'
D_WAIT:
JBC SSIO1_CON,0,D_WAIT ;wait for received
STB SSIO1_BUF,RESULT ;store rec. data
SJMP HERE
END



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