SH7011 Datasheet, PDF (136/292 Pages) Renesas Technology Corp – CMOS single-chip microprocessors

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–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
Channel 1, channel 2
Upper 16 Bits
TCNT1
Lower 16 Bits
TCNT2
Procedure for Setting Cascade Connection Mode (Figure 8.21):
1. Set the TPSC2–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 ⁽¹⁾
Start counting
(2)
Cascade connection operation
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
register.
127