Maxim Integrated MAXQ7667 - Manual (Page 92)

5-17 __________________________________________________________________________________________________________
MAXQ7667 User’s Guide
PORT P0
PIN
FUNCTION
TYPE
FUNCTION ENABLED WHEN MULTIPLEXING/PRIORITIZATION
Special
TXEN—As TXEN this pin can be
used to control the transmit enable
of an external driver (active low).
This pin defaults to TXEN any time
the UART is used. TXEN is low
when the UART is transmitting, and
is resistively pulled high/low when
it is not.
SBUF loaded with data
P0.2/TXEN
Alternate External Interrupt 2, Input (EIE0.2) EX2 = 1
This port pin defaults to a weak pullup input
after a reset. When the UART is transmitting,
this pin is driven low (active low) to denote
that the UART is transmitting. When the
UART becomes idle the pin returns to the
configured pullup/down state (so it should
be left as a pullup in order to use this pin to
enable an external transceiver).
Special T0—Timer 0 (Type 2) Output (T2CNA0.6) T2OE0 =1
Special T0—Timer 0 (Type 2) Counter Input
(T2CFG0.0) C/T2 = 1 (T2CFG0[2:1])
CCF[1:0] = 00b (T2CNA0.6) T2OE0
must be 0
Special T0—Timer 0 (Type 2) Gate Input
(T2CNA0.0)G2EN = 1 or
(T2CFG0[2:1])
CCF[1:0] = 11b and
(T2CNA0.2) CPRL2 = 1
(T2CNA0.6) T2OE0 must be 0
(T2CFG0.0) C/T2 must be 0
Special
ADCCTL—As ADCCTL this user-
programmable rising or falling
edge controls the SAR ADC
sampling instant and start of
conversion. Optionally, the other
edge can be used to enable the
ADC and begin acquiring prior to
sampling.
SARC.SARS[2:0] =
"100" or "101"
P0.3/T0/
ADCCTL
Alternate External Interrupt 3, Input (EIE0.3) EX3 = 1
This port pin defaults to a weak pullup input
after a reset. If the T2OE0 is set, the pin is a
timer output, but the ADCCTL input path still
operates (i.e., output timer pulse can come
back in as ADCCTL). When the SAR's
conversion trigger is selected as "100" this
pin is used as the ADCCTL strobe. When
SARC.SARS = "101" this pin is inverted and
then used as the ADCCTL strobe. The SAR's
behavior then depends on SARC.SARDUL,
which selects single edge (when 0) or dual
edge (when 1) conversions.
Special
T0B—Timer 0 (Type 2) Secondary
Output
(T2CNB0.6)T2OE1 = 1
P0.4/T0B
Alternate External Interrupt 4, Input (EIE0.4) EX4 = 1
This port pin defaults to a weak pullup input
after a reset. If interrupt 4 is enabled, T0B is
not permitted at this pin.
Special T1—Timer 1 (Type 2) Output (T2CNA1.6) T2OE0 = 1
Special T1—Timer 1 (Type 2) Counter Input
(T2CFG1.0) C/T2 = 1
(T2CFG1[2:1])
CCF[1:0] =! 00b
(T2CNA1.6) T2OE0 must be 0
Special T1—Timer 1 (Type 2) Gate Input
(T2CNA1.0) G2EN = 1 or
(T2CFG1[2:1])
CCF[1:0] = 11b and
(T2CNA1.2) CPRL2 = 1
(T2CNA1.6) T2OE0 must be 0
(T2CFG1.0) C/T2 must be 0
P0.5/T1
Alternate External Interrupt 5, Input (EIE0.5) EX5 = 1
This port pin defaults to a weak pullup input
after a reset. If interrupt 5 is enabled, T1 is
not permitted at this pin.
Table 5-4. Port P0 Pin Special and Alternate Functions (continued)