upd70f3402 Renesas Electronics Corporation., upd70f3402 Datasheet - Page 87

• Manufacturer Part Number: upd70f3402
• Description: 32-/16-bit Single-chip Microcontroller With Can Interface
• Manufacturer: Renesas Electronics Corporation.

Notes: 1. On input to RESET pin (external reset): OCDM0 = 1
Caution:
Symbol
OCDM
R/W
(b) On-chip debug mode register (OCDM)
This register is used to switch between the normal operation mode and the on-chip debug mode.
The OCDM register is a special register (refer to 3.2.3 ”Special registers” on page 70). Writing is
possible only using a specific sequence so that its contents cannot be rewritten by mistake in case
of inadvertent program loops.
When OCDM0 bit is set to 1 and DRST pin input is high level, the on-chip debug mode is selected.
Since after reset the initial value of OCDM0 bit is 1, when not using the on-chip debug function, it
is necessary to clear the OCDM0 bit and maintain the DRST pin at low level until the OCDM0 bit is
cleared.
This register can be read and written in 8-bit or 1-bit units.
2. P97/SIB1/{DDI}
R/W
On power-on reset: OCDM0 = 0
On occurrence of internal reset (other than power-on clear): OCDM register holds the value
before occurrence of reset.
P98/SOB1/{DCK}
P99/SCKB1/{DMS}
P910/CS301/{DDO}
P911/{DRST}
A pull-down resistor function is also associated with the OCDM register setting.
When OCDM0=1, the port pull-down resistor is enabled, likewise when OCDM0=0 the
pull-down is disabled. Refer to Chapter 4 ”Port Functions” on page 105 for more
information.
7
0
Figure 3-26: On-Chip Debug Mode Register (OCDM) Format
R/W
OCDM0
6
0
0
1
R/W
Normal operation mode
DRST pin = low level: Normal operation mode
DRST pin = high level: On-chip debug mode
5
0
User’s Manual U16702EE3V2UD00
R/W
Chapter 3 CPU Function
4
0
R/W
3
0
Operation mode
R/W
2
0
R/W
1
0
OCDM0 FFFFF9FCH
R/W
0
Address
After reset
01H
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