st10f269z1 STMicroelectronics, st10f269z1 Datasheet - Page 75

• Manufacturer Part Number: st10f269z1
• Description: St10f269 16-bit Mcu With Mac Unit, 256k Byte Flash Memory And 12k Byte Ram
• Manufacturer: STMicroelectronics

ST10F269
Pin P3.12 (BHE/WRH) is another pin with an
alternate output function, however, its structure is
slightly different.
After reset the BHE or WRH function must be
used
configuration. In either of these cases, there is no
Figure 29 : Block Diagram of Pins P3.15 (CLKOUT) and P3.12 (BHE/WRH)
Note: Enabling the BHE or WRH function automatically enables the P3.12 output driver. Setting bit
DP3.12=’1’ is not required.
During bus hold pin P3.12 is switched back to its standard function and is then controlled by
DP3.12 and P3.12. Keep DP3.12 = ’0’ in this case to ensure floating in hold mode.
depending
Read DP3.x
Write DP3.x
Port Output
Read P3.x
Write P3.x
Direction
Latch
Latch
on
the
MUX
system
Alternate
Data
Output
1
0
Alternate
Function
Enable
“1”
start-up
1
0
1
0
MUX
MUX
possibility to program any port latches before.
Thus, the appropriate alternate function is
selected automatically. If BHE/WRH is not used in
the system, this pin can be used for general
purpose I/O by disabling the alternate function
(BYTDIS = ‘1’ / WRCFG=’0’).
Clock
Latch
Input
Output
Buffer
12 - PARALLEL PORTS
x = 15, 12
P3.12/BHE
P3.15/CLKOUT
75/184