Typical Connection With The Host - Renesas M32R/ECU Series User Manual

14

14.4 Typical Connection with the Host

The host uses a serial synchronous interface to transfer data. The clock for synchronous communication should
be generated by the host. An example for connecting the RTD and host is shown below.
M32R/ECU
Note 1: This applies to the case where the RTDACK level is checked between transfer frames.
Figure 14.4.1 Connecting the RTD and Host
The RTD communication is performed in a fixed length of 32 bits per frame. Because serial interfaces generally
handle data in 8-bit units, data is transferred separately in four operations, 8 bits at a time. The RTDACK signal is
used to verify that communication is performed normally.
The RTDACK signal goes low after a command is sent, providing a means of verifying the communication status.
When issuing the VER command, the RTDACK signal is pulled low for only one clock period. Therefore, after
sending 32 bits in one frame via a serial interface, turn off RTDCLK output and check that RTDACK is low. That
way, it is possible to know whether the RTD is communicating normally.
If it is desirable to identify the type of transmitted command by the width of RTDACK, use the microcomputer's
internal measurement timer (to count RTDCLK pulses while RTDACK is low), or design a dedicated circuit.
RTDCLK
RTDRXD
RTDTXD
RTDACK
Figure 14.4.2 Example of Communication with the Host (when Using VER Command)
RTDCLK
RTDRXD
RTDTXD
RTDACK
Transfer of one frame (32 bits)
(8 bits)
(8 bits)
REAL TIME DEBUGGER (RTD)
14.4 Typical Connection with the Host
Host
microprocessor
SCLK
RXD
TXD
(Note 1)
PORT
(8 bits)
Check that the RTDACK signal is low.
14-11
Transfer of the
next frame
1 2
32180 Group User's Manual (Rev.1.0)