Renesas Asynchronous SH7145F Manual do Utilizador descarregar pdf (Página 6)

SH7145F

Synchronous Serial Data Transmission

REJ06B0352-0100O/Rev.1.00 March 2004 Page 6 of 16

3. Operation

Figure 3 shows the operation of synchronous mode data transmission in the task example. To help

explain figure 3, table 2 lists the software and hardware processing that is performed.

TDR_0

(register)

TSR_0

(register)

TDRE

(SSR_0 bit)

(1)

(2)

(3)

(4) (5)

(6)

(7)

(8)

Data bits D0 to D7

2nd byte

Data bits D0 to D7

1st byte

Figure 3 Data Transmission Operation

Table 2 Processing

Software Processing Hardware Processing

(1) Write transmit data to TDR_0 —

(2) Clear TDRE flag in SSR_0 to 0 —

(3) — TransferdatafromTDR_0toTSR_0

(4) — Set TDRE flag in SSR_0 to 0 and output

transmit data from pin TXD0

(5) Confirm TDRE is 0 and send next

transmit data to TDR_0

—

(6) Clear TDRE flag in SSR_0 to 0

(7) — TransferdatafromTDR_0toTSR_0

(8) — When output of previous data finishes, set

TDRE flag in SSR_0 to 1 and output

transfer data from pin TXD0

(9) Repeat Repeat

1 2 3 4 5 6 7 8 9 10 11 ... 15 16

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