CHAPTER 4 BUS CONTROL FUNCTION
User’s Manual U13850EJ6V0UD
137
4.8 Bus Timing
The V850/SB1 and V850/SB2 can execute read/write control for an external device using the following two modes.
•
Mode using DSTB, R/W, LBEN, UBEN, and ASTB signals
•
Mode using RD, WRL, WRH, and ASTB signals
Set these modes by using the BIC bit of the system control register (SYC) (see
4.2.2 (1) System control register
(SYC)
).
Figure 4-8. Memory Read (1/4)
(a)
0 waits
T1
T2
T3
CLKOUT (output)
A16 to A21 (output)
AD0 to AD15 (I/O)
Address
Data
Address
ASTB (output)
R/W (output)
DSTB, RD (output)
UBEN, LBEN (output)
WAIT (input)
WRH, WRL (output)
H
A1 to A15 (output)
Address
Remarks 1.
{
indicates the sampling timing when the number of programmable waits is set to 0.
2.
The broken line indicates the high-impedance state.