
CHAPTER 31 ON-CHIP DEBUG FUNCTION
User’s Manual U17790EJ2V0UD
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(3) DMS
This is a transfer mode select signal. The transfer status in the debug unit changes depending on the level of
the DMS signal.
(4) DDI
This is a data input signal. It is sampled in the on-chip debug unit at the rising edge of DCK.
(5) DDO
This is a data output signal. It is output from the on-chip debug unit at the falling edge of the DCK signal.
(6) VDD, EVDD
This signal is used to detect VDD of the target system. If VDD from the target system is not detected, the
signals output from the on-chip debug emulator (DRST, DCK, DMS, DDI, FLMD0, and RESET) go into a high-
impedance state.
(7) FLMD0
The flash self programming function is used for the function to download data to the flash memory via the
integrated debugger. During flash self programming, the FLMD0 pin must be kept high. In addition, connect a
pull-down resistor to the FLMD0 pin.
The FLMD0 pin can be controlled in either of the following two ways.
<1>
To control from on-chip debug emulator
Connect the FLMD0 signal of the on-chip debug emulator to the FLMD0 pin.
In the normal mode, nothing is driven by the on-chip debug emulator (high impedance).
During a break, the on-chip debug emulator raises the FLMD0 pin to the high level when the download
function of the integrated debugger is executed.
<2>
To control from port
Connect any port of the device to the FLMD0 pin.
The same port as the one used by the user program to realize the flash self programming function may
be used.
On the console of the integrated debugger, make a setting to raise the port pin to high level before
executing the download function, or lower the port pin after executing the download function.
For details, refer to the ID850QB (Integrated Debugger) Operation User’s Manual.
(8) RESET
This is a system reset input pin. If the DRST pin is made invalid by the value of the OCDM0 bit of the OCDM
register set by the user program, on-chip debugging cannot be executed. Therefore, reset is effected by the
on-chip debug emulator, using the RESET pin, to make the DRST pin valid (initialization).