NEC V850ES/KE1+, User Manual

Page: 69 / 709

CHAPTER 3 CPU FUNCTIONS
User’s Manual U16896EJ2V0UD
69
Peripheral Function Register Name Access k
WDTM1 Write 1 to 5 Watchdog timer 1 (WDT1)
<Calculation of number of waits
Note 1
>
k = {(1/f
X
)
×
2/((2 + m)/f
CPU
)} + 1
f
X
: Main clock oscillation frequency
Watchdog timer 2 (WDT2) WDTM2 Write 3 (fixed)
TP0CCR0, TP0CCR1,
TP0CNT
Read 1
<Calculation of number of waits
Note 1
>
k = {(1/f
XX
)/((2 + m)/f
CPU
)} + 1
TP0CCR0, TP0CCR1 Write 0 to 2
16-bit timer/event counter P0 (TMP0)
<Calculation of number of waits
Note 1
>
k = {(1/f
XX
)
×
5/((2 + m)/f
CPU
)}
A wait occurs when performing continuous write to same register
16-bit timer/event counter 01 (TM01) TMC01 Read-modify-write 1 (fixed)
A wait occurs during write
I
2
C0
Note 2
IICS0 Read 1 (fixed)
Asynchronous serial interfaces 0, 1
(UART0, UART1)
ASIS0, ASIS1 Read 1 (fixed)
Real-time output function 0 (RTO0) RTBL0, RTBH0 Write (when
RTPC0.RTPOE0 bit = 0)
1
ADM, ADS, PFM, PFT Write 1 to 2
ADCR, ADCRH Read 1 to 2
A/D converter
<Calculation of number of waits
Note 1
>
k = {(1/f
XX
)
×
2/[(2 + m)/f
CPU
]} + 1
Notes 1. In the calculation of number of waits, the fractional part of its result must be multiplied by (1/f
CPU
)
and rounded down if (1/f
CPU
)/(2 + m) or lower, and rounded up if (1/f
CPU
)/(2 + m) is exceeded.
2. I
2
C0 is available only in the
μ
PD703302Y and 70F3302Y.
Cautions 1. If fetched from the internal ROM or internal RAM, the number of waits is as shown above.
If fetched from the external memory, the number of waits may be decreased below these.
The effect of the external memory access cycles varies depending on the wait settings
and the like. However, the number of waits shown above is the maximum value, so no
higher value is generated.
2. Accessing the registers in which a wait occurs using an access method that causes a
wait is prohibited in the following statuses. If a wait cycle is generated, it can only be
cleared by a reset.
•
When the CPU operates with the subclock and the main clock oscillation is stopped
•
When the CPU operates with the internal oscillation clock
Remark In the calculation for the number of waits:
f
CPU
: CPU clock frequency
f
XX
: Main clock frequency
m: Set value of bits 2 to 0 of the VSWC register
When the VSWC register = 00H: m = 0
When the VSWC register = 01H: m = 1
<R>
<R>