Filter
Top Products
144
CHAPTER 4 BUS INTERFACE
❍
16-bit bus width
Figure 4.16-8 External Bus Access for 16-bit Bus Width
MSB LSB
00 01 00 01 00 01
10 11 10 11 10 11
16bit
00 01 00 01 00 01
10 11 10 11 10 11
00 01 00 01 00 01
10 11 10 11 10 11
00 01
10 11
00 01
10 11
00 01
10 11
PA1/PA0 : Lower 2 bits of address specified by program
Output A1/A0 : Lower 2 bits of output address
: First byte location of output address
: Data byte location for access
1) to 2) : Bus access count
(A) Word access
(B) Half-word access
(C) Byte access
Output A1/A0='10' Output A1/A0='10' Output A1/A0='10'
Output A1/A0='00' Output A1/A0='00' Output A1/A0='00' Output A1/A0='00'
Output A1/A0='10'
(a) PA1/PA0='00' (b) PA1/PA0='01' (c) PA1/PA0='10' (d) PA1/PA0='11'
(a) PA1/PA0='00' (b) PA1/PA0='01' (c) PA1/PA0='10' (d) PA1/PA0='11'
Output A1/A0='00' Output A1/A0='00' Output A1/A0='10' Output A1/A0='10'
(a) PA1/PA0='00' (b) PA1/PA0='01' (c) PA1/PA0='10' (d) PA1/PA0='11'
Output A1/A0='00' Output A1/A0='01' Output A1/A0='10' Output A1/A0='11'