M16C62_M Datasheet, PDF (423/615 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/60 SERIES

SI/O3, 4
Mitsubishi microcomputers
M16C / 62A Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
2.6 SI/O3, 4 Usage
2.6.1 Overview of the SI/O3,4 usage
SI/O3, 4 carries out 8-bit data communications in synchronization with the clock. The following is an
overview of the SI/O3, 4 usage.
(1) Transmission/reception format
8-bit data
(2) Transfer rate
If the internal clock is selected as the transfer clock, the divide-by-2 frequency, resulting from the bit
rate generator division, becomes the transfer rate. The bit rate generator count source can be se-
lected from the following: f1, f8, and f32. Clocks f1, f8, and f32 are derived by dividing the CPU’s main
clock by 1, 8, and 32 respectively.
Furthermore, if an external clock is selected as the transfer clock, the clock frequency input to the CLK
pin becomes the transfer rate.
(3) Function selection
For SI/O3, 4, the following functions can be selected:
(a) Function for choosing which bit to transmit first
This function is to choose whether to transmit data from bit 0 or from bit 7. Choose either of the
following:
• LSB first Data is transmitted from bit 0.
• MSB first Data is transmitted from bit 7.
(b) Choosing output level when not transferring
• Internal clock
High-impedance output.
• External clock "H" or "L" output level is selected.
(6) Input to the serial I/O and the direction register
To input an external signal to the serial I/O, set the direction register of the relevant port to input.
(7) Pins related to the SI/O3, 4
• CLK3, CLK4 pins Input/output pins for the transfer clock
• SIN3, SIN4 pins
Input pins for data
• SOUT3, SOUT4 pins Output pins for data
(8) Registers related to the SI/O3, 4
Figure 2.6.1 shows the memory map of SI/O3, 4-related registers, and Figures 2.6.2 show SI/O3, 4-
related registers.
004816 _{SI/O4 interrupt control register (S4IC)}
004916 _{SI/O3 interrupt control register (S3IC)}
036016
036116
036216
036316
036416
036516
036616
036716
SI/O3 transmit/receive register (S3TRR)
SI/O3 transmit/receive control register (S3C)
SI/O3 bit rate generator (S3BRG)
SI/O4 transmit/receive register (S4TRR)
SI/O4 control register (S4C)
SI/O4 bit rate generator (S4BRG)
Figure 2.6.1. Memory map of serial I/O3, 4-related registers
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