
Rev. 2.0, 09/02, page 338 of 732
11.9
Port Output Enable (POE)
The port output enable (POE) can be used to establish a high-impedance state for high-current
pins, by changing the
POE0
to
POE3
pin input, depending on the output status of the high-current
pins (PE9/TIOC3B/SCK3/
TRST
*, PE11/TIOC3D/RXD3/TDO*, PE12/TIOC4A/TXD3/TCK*,
PE13/TIOC4B/
MRES
, PE14/TIOC4C/DACK0, PE15/TIOC4D/DACK1/
IRQOUT
). It can also
simultaneously generate interrupt requests.
The high-current pins can also be set to high-impedance regardless of whether these pin functions
are selected in cases such as when the oscillator stops or in software standby mode. For details,
refer to section 17.1.11, High-Current Port Control Register (PPCR).
However, when using the E10A, the high-impedance function is disabled when an oscillation stop
is detected, port output enable (POE), or in the software standby state for the three pins of
PE9/TIOC3B/SCK3/
TRST
, PE11/TIOC3D/RXD3/TDO, and PE12/TIOC4A/TXD3/TCK of the
SH7145.
Note: * Only in the SH7145.
11.9.1
Features
Each of the
POE0
to
POE3
input pins can be set for falling edge, P
φ
/8
×
16, P
φ
/16
×
16, or
P
φ
/128
×
16 low-level sampling.
High-current pins can be set to high-impedance state by
POE0
to
POE3
pin falling-edge or
low-level sampling.
High-current pins can be set to high-impedance state when the high-current pin output levels
are compared and simultaneous low-level output continues for one cycle or more.
Interrupts can be generated by input-level sampling or output-level comparison results.