CHAPTER 5 BBR
Preliminary User's Manual A14874EJ3V0UM
123
5.2 Wait Insertion Function
The BBR is equipped with a wait insertion function for connection with low-speed peripheral macros that are
connected to the NPB. The NPB strobe wait control register (VSWC) is used to set up this function.
The VSWC register sets the setup wait length and VPSTB wait length (see
Figure 5-6
). The number of waits can
be set in the range from 0 to 7 clocks based on the internal system clock (VBCLK).
The VSWC register can be read or written in 8-bit or 1-bit units.
Figure 5-6. NPB Strobe Wait Control Register (VSWC) (1/2)
7
6
5
4
3
2
1
0
VSWC
0
SUWL2
SUWL1
SUWL0
0
VSWL2
VSWL1
VSWL0
Address
FFFFF06EH
After reset
77H
Bit position
Bit name
Function
Sets the setup wait length.
SUWL2
SUWL1
SUWL0
Setup 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
6 to 4
SUWL2 to
SUWL0
Remark
t
CLK
: Internal system clock (VBCLK) cycle
Caution Bits 7 and 3 of the VSWC register must be set to 0. The operation when these bits are set to
1 is not guaranteed.