R01UH0823EJ0100 Rev.1.00
Page 1331 of 1823
Jul 31, 2019
RX23W Group
38. Serial Peripheral Interface (RSPIa)
38.
Serial Peripheral Interface (RSPIa)
In this section, “PCLK” is used to refer to PCLKB.
38.1
Overview
This MCU includes one channel of Serial Peripheral Interface (RSPI).
The RSPI channels are capable of high-speed, full-duplex synchronous serial communications with multiple processors
and peripheral devices.
lists the specifications of the RSPI, and
shows a block diagram of the RSPI.
In this section, m as used with the RSPI command registers (SPCMDm) indicates 0 to 7.
Table 38.1
RSPI Specifications (1/2)
Item
Description
Number of channels
One channel
RSPI transfer functions
Use of MOSI (master out/slave in), MISO (master in/slave out), SSL (slave select), and RSPCK (RSPI
clock) signals allows serial communications through SPI operation (4-wire method) or clock
synchronous operation (3-wire method).
Transmit-only operation is available.
Communication mode: Full-duplex or transmit-only can be selected.
Switching of the polarity of RSPCK
Switching of the phase of RSPCK
Data format
MSB first/LSB first selectable
Transfer bit length is selectable as 8, 9, 10, 11, 12, 13, 14, 15, 16, 20, 24, or 32 bits.
128-bit transmit/receive buffers
Up to four frames can be transferred in one round of transmission/reception (each frame consisting of
up to 32 bits).
Bit rate
In master mode, the on-chip baud rate generator generates RSPCK by frequency-dividing PCLK (the
division ratio ranges from divided by 2 to divided by 4096).
In slave mode, the minimum PCLK clock divided by 8 can be input as RSPCK (the maximum frequency
of RSPCK is that of PCLK divided by 8).
Width at high level: 4 cycles of PCLK; width at low level: 4 cycles of PCLK
Buffer configuration
Double buffer configuration for the transmit/receive buffers
128 bits for the transmit/receive buffers
Error detection
Mode fault error detection
Overrun error detection*
Parity error detection
SSL control function
Three SSL pins (SSLA0, SSLA1, and SSLA3) for each channel
In single-master mode, SSLA0, SSLA1, and SSLA3 pins are output.
In multi-master mode:
SSLA0 pin for input, and SSLA1, SSLA3 pins for either output or unused.
In slave mode:
SSLA0 pin for input, and SSLA1, SSLA3 pins for unused.
Controllable delay from SSL output assertion to RSPCK operation (RSPCK delay)
Range: 1 to 8 RSPCK cycles (set in RSPCK-cycle units)
Controllable delay from RSPCK stop to SSL output negation (SSL negation delay)
Range: 1 to 8 RSPCK cycles (set in RSPCK-cycle units)
Controllable wait for next-access SSL output assertion (next-access delay)
Range: 1 to 8 RSPCK cycles (set in RSPCK-cycle units)
Function for changing SSL polarity
Control in master transfer
A transfer of up to eight commands can be executed sequentially in looped execution.
For each command, the following can be set:
SSL signal value, bit rate, RSPCK polarity/phase, transfer data length, MSB/LSB first, burst, RSPCK
delay, SSL negation delay, and next-access delay
A transfer can be initiated by writing to the transmit buffer.
MOSI signal value specifiable in SSL negation
RSPCK auto-stop function