CHAPTER 5 BBR
Preliminary User's Manual A14874EJ3V0UM
124
Figure 5-6. NPB Strobe Wait Control Register (VSWC) (2/2)
Bit position
Bit name
Function
Sets the VPSTB wait length.
VSWL2
VSWL1
VSWL0
VPSTB wait length
0
0
0
0 (no waits)
0
0
1
1
×
t
CLK
0
1
0
2
×
t
CLK
0
1
1
3
×
t
CLK
1
0
0
4
×
t
CLK
1
0
1
5
×
t
CLK
1
1
0
6
×
t
CLK
1
1
1
7
×
t
CLK
2 to 0
VSWL2 to
VSWL0
Remark
t
CLK
: Internal system clock (VBCLK) cycle
VPSTB (Output)
VPA13 to VPA0 (Output)
VPSTB wait
0.5 clock
Setup wait
VBCLK (Input)
1 clock
1.5 clock
Be sure to set values for the setup wait and VPSTB wait lengths at each operation frequency that are the same as
or greater than the number of waits shown in Table 5-1 below.
Table 5-1. Setting of Setup Wait, VPSTB Wait Lengths at Each Operation Frequency
Operation Frequency
Wait Length
To 25 MHz
To 33 MHz
To 50 MHz
To 81 MHz
To 100 MHz
Setup wait length (set using bits SUWL2 to SUWL0)
1
1
1
2
2
VPSTB wait length (set using bits VSWL2 to VSWL0)
1
2
4
5
6
Caution These setting values are not guaranteed, so be sure to set the number of waits appropriate to the
system after verifying operation.