Operation; Reset Operation By Reset Pin; Table 19-1: Hardware Status On Reset Pin Input - NEC V850E/RS1 User Manual

19.3 Operation

19.3.1 Reset operation by RESET pin

When a low level is input to the RESET pin, the system is reset, and each hardware unit is initialized.
When the level of the RESET pin is changed from low to high, the reset status is released and the oscil-
lation stabilization timer begins counting (reset value of OSTS register: 2
elapses, then the CPU starts program execution.
Main clock oscillator (f
Ring-OSC generator
Peripheral clock (f
Internal system clock (f
CPU clock (f
CPU
Watchdog timer 2
Internal RAM
I/O lines (ports/alternate-function
pins)
On-chip peripheral I/O registers
Other on-chip peripheral functions Operation stops
Note: Because the V850E/RS1 supports a boot swap function, the firmware uses part of the internal
Caution:
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Chapter 19 RESET Function

Table 19-1: Hardware Status on RESET Pin Input

Item
)
Continues oscillation
X
Stops oscillation
to f /1,024)
Stops operation
XX XX
),
CLK
Stops operation
)
CPU
Initialized
Stops operation
undefined after a reset while power is on or if a data access to RAM (by the
CPU) and a reset input conflict (data corrupted). Otherwise, retains value
immediately before reset input
High impedance
Initialized to specified status, OCDM register is set (01H).
RAM after the internal system reset is released. Therefore, the contents of some areas (RAM
size is 3FC800H-3FC895H into 10K byte and 3FB000H-3FB095H into 16K byte and 2K byte
down from the uppermost address 3FEFFFH- 3FE7FFH) of the RAM are not retained even
when power-on reset is executed.
The on-chip debug mode (flash memory products only) may be set depending on the
pin status after reset has been released. For details, see Chapter 4 "Port Functions"
on page 105 and Chapter 22 "On-Chip Debug Function" on page 767.
User's Manual U16702EE3V2UD00
During Reset
Starts oscillation
Starts operation after oscillation stabili-
zation time (initialized to f
Starts operation after oscillation stabili-
zation time (initialized to f
Program execution starts after oscilla-
tion stabilization time
Starts operation
Note
.
Operation can be started after securing
oscillation stabilization time
13
/f ). When the OSTS timer
X
After Reset
× 4)
XX
× 4)
XX
741