UPD78F0890GK(A)-GAJ-AX NEC, UPD78F0890GK(A)-GAJ-AX Datasheet - Page 124

• Manufacturer Part Number: UPD78F0890GK(A)-GAJ-AX
• Description: 8BIT MCU, 128K FLASH, 7K RAM, LQFP
• Manufacturer: NEC

Specifications of UPD78F0890GK(A)-GAJ-AX

• Controller Family/series: UPD78F
• No. Of I/o's: 55
• Ram Memory Size: 7KB
• Cpu Speed: 20MHz
• No. Of Timers: 10
• No. Of Pwm: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 128KB
• Oscillator Type: External, Internal

<R>
5.5 Cautions on 1-Bit Manipulation Instruction for Port Register n (Pn)
output latch value of an input port that is not subject to manipulation may be written in addition to the targeted bit.
124
P11 to P17
When a 1-bit manipulation instruction is executed on a port that provides both input and output functions, the
Therefore, it is recommended to rewrite the output latch when switching a port from input mode to output mode.
<Example>
Explanation:
Port 1 output latch
0
P10
0
0
When P10 is an output port, P11 to P17 are input ports (all pin statuses are high level), and the port
latch value of port 1 is 00H, if the output of output port P10 is changed from low level to high level
via a 1-bit manipulation instruction, the output latch value of port 1 is FFH.
The targets of writing to and reading from the Pn register of a port whose PMnm bit is 1 are the
output latch and pin status, respectively.
A 1-bit manipulation instruction is executed in the following order in the 78K0/FE2.
<1> The Pn register is read in 8-bit units.
<2> The targeted one bit is manipulated.
<3> The Pn register is written in 8-bit units.
In step <1>, the output latch value (0) of P10, which is an output port, is read, while the pin statuses
of P11 to P17, which are input ports, are read. If the pin statuses of P11 to P17 are high level at
this time, the read value is FEH.
The value is changed to FFH by the manipulation in <2>.
FFH is written to the output latch by the manipulation in <3>.
1-bit manipulation instruction for P10 bit
<1> Port register 1 (P1) is read in 8-bit units.
<2> Set the P10 bit to 1.
<3> Write the results of <2> to the output latch of port register 1 (P1)
0
in 8-bit units.
Pin status: High level
Low-level output
0
In the case of P10, an output port, the value of the port output latch (0) is read.
In the case of P11 to P17, input ports, the pin status (1) is read.
0
Figure 5-27. Bit Manipulation Instruction (P10)
0
CHAPTER 5 PORT FUNCTIONS
0
User’s Manual U17554EJ4V0UD
1-bit manipulation
instruction
(set1 P1.0)
is executed for P10
bit.
P11 to P17
Port 1 output latch
1
P10
1
1
1
Pin status: High level
High-level output
1
1
1
1