0X5209: P0 Port Key-Entry Reset Configuration Register (P0_Krst) - Epson S1C17704 Technical Manual

10 I/O PORTS (P)

0x5209: P0 Port Key-Entry Reset Configuration Register (P0_KRST)

Register name Address Bit
P0 Port Key- 0x5209 D7–2 –
Entry Reset (8 bits)
D1–0 P0KRST[1:0] P0 port key-entry reset
Configuration
Register
(P0_KRST)
D[7:2] Reserved
D[1:0] P0KRST[1:0]: P0 Port Key-Entry Reset Configuration Bits
Selects a port configuration for the P0 port key-entry reset function.
The P0 key-entry reset is one of the initial reset features and it generates an initial reset signal when the
ports selected here is set to low level at the same time.
For example, if P0KRST[1:0] is set to 0x3, an initial reset will take place when the four ports P00–P03
are set to low level at the same time.
Set P0KRST[1:0] to 0x0 when this function is not used.
Notes: • When using the P0 port key-entry reset function, make sure that the designated input ports
will not be simultaneously set to low level while the application program is running.
• The P0 port key-entry reset function cannot be used for power-on reset as it must be
enabled with software.
• The P0 port key-entry reset function cannot be used in SLEEP mode.
10-20
Name Function
reserved
configuration
Table 10.8.3 Configuration of P0 Port Key-Entry Reset
P0KRST[1:0]
0x3
0x2
0x1
0x0
EPSON
Setting
–
P0KRST[1:0] Configuration
0x3 P0[3:0] = 0
0x2 P0[2:0] = 0
0x1 P0[1:0] = 0
0x0 Disable
Port used for resetting
P00, P01, P02, P03
P00, P01, P02
P00, P01
Not used
(Default: 0x0)
Init. R/W Remarks
– – 0 when being read.
0x0 R/W
S1C17704 TECHNICAL MANUAL