HD64F2149 Datasheet, PDF (614/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

HICR0 Bit 4—Fast A20 Gate Function Enable (FGA20E): Enables or disables the fast A20
gate function. When the fast A20 gate is disabled, the normal A20 gate can be implemented by
firmware operation of the P81 output.
When the fast A20 gate function is enabled, the DDR bit for P81 must not be set to 1.
HICR0
Bit 4
FGA20E
0
1
Description
Fast A20 gate function disabled
• Other function of pin P81 is enabled
• GA20 output internal state is initialized to 1
(Initial value)
Fast A20 gate function enabled
• GA20 pin output is open-drain (external V_CC pull-up resistor required)
HICR0 Bit 2—PME Output Enable (PMEE)
HICR1 Bit 2—PME Output Bit (PMEB)
These bits control PME output. PME pin output is open-drain, and an external pull-up resistor is
needed to pull the output up to V_CC.
When the PME output function is used, the DDR bit for P80 must not be set to 1.
HICR0
Bit 2
PMEE
0
1
HICR1
Bit 2
PMEB
0
1
0
1
Description
PME output disabled, other function of pin P80 is enabled
PME output disabled, other function of pin P80 is enabled
PME output enabled, PME pin output goes to 0 level
PME output enabled, PME pin output is high-impedance
(Initial value)
580