SH7018 datasheet(150/431 Pages) RENESAS

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8.4.5

Cascade Connection Mode

Cascade connection mode is a function that connects the 16-bit counters of two channels together

to act as a 32-bit counter.

This function operates by using the TPSC2 to TPSC0 bits of the TCR register to set the channel 1

counter clock to count by TCNT2 counter overflow.

Table 8.6 shows the cascade connection combinations.

Table 8.6

Cascade Connection Combinations

Combination

Upper 16 Bits

Lower 16 Bits

Channel 1, channel 2

TCNT1

TCNT2

Procedure for Setting Cascade Connection Mode (Figure 8.21):

1. Set the TPSC2 to TPSC 0 bits of the channel 1 timer control register (TCR) to B'111 to select

“count by TCNT2 overflow.”

2. Set the CST bits corresponding to the upper and lower 16 bits in the TSTR to 1 to start the

count operation.

Cascade connection operation

Select cascade connection

Start counting

Cascade connection operation

(1)

(2)

Figure 8.21 Procedure for Selecting Cascade Connection Mode

Cascade Connection Mode Examples—Input Capture: Figure 8.22 shows an example of

operation when the TCNT1 counter is set to count on TCNT2 overflow, the TGR1A and TGR2A

registers are set as input capture registers, and the TIOC pin rising edge is selected.

Through simultaneous input of the rising edge to the TIOC1A and TIOC2A pins, 32-bit data is

transferred, with the upper 16 bits to the TGR1A register and the lower 16 bits to the TGR2A

SH7018 Datasheet(PDF) 150 Page - Renesas Technology Corp