TMS320C5505_15 Datasheet, PDF (18/157 Pages) Texas Instruments – TMS320C5505 Fixed-Point Digital Signal Processor

TMS320C5505
SPRS660F – AUGUST 2010 – REVISED SEPTEMBER 2013
2.5.2 RTC Terminal Functions
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Table 2-6. Real-Time Clock (RTC) Terminal Functions
SIGNAL
NAME
RTC_XO
NO.
TYPE ⁽¹⁾
(2)
OTHER ^{(3) (4)}
DESCRIPTION
Real-time clock oscillator output. This pin operates at the RTC core voltage,
CV_DDRTC, and supports a 32.768-kHz crystal.
A9
O/Z
–
CV_DDRTC
If the RTC oscillator is not used, it can be disabled by connecting RTC_XI to
CV_DDRTC and RTC_XO to floating or grounded. A voltage must still be applied to
CV_DDRTC by an external power source (see Section 4.2, Recommended Operating
Conditions). None of the on-chip LDOs can power CV_DDRTC.
Note: When RTC oscillator is disabled, the RTC registers (I/O address range
1900h – 197Fh) are not accessible.
Real-time clock oscillator input.
RTC_XI
B9
I
RTC_CLKOUT D8
O/Z
WAKEUP
E8 I/O/Z
–
CV_DDRTC
–
DV_DDRTC
–
DV_DDRTC
If the RTC oscillator is not used, it can be disabled by connecting RTC_XI to
CV_DDRTC and RTC_XO to ground (V_SS). A voltage must still be applied to CV_DDRTC
by an external power source (see Section 4.2, Recommended Operating
Conditions). None of the on-chip LDOs can power CV_DDRTC.
Note: When RTC oscillator is disabled, the RTC registers (I/O address range
1900h – 197Fh) are not accessible.
Real-time clock output pin. This pin operates at DV_DDRTC voltage. The
RTC_CLKOUT pin is enabled/disabled through the RTCCLKOUTEN bit in the RTC
Power Management Register (RTCPMGT). At reset, the RTC_CLKOUT pin is
disabled (high-impedance [Hi-Z]).
The pin is used to WAKEUP the CPU from idle instruction. This pin defaults to an
input at reset, but can also be configured as an active-low open-drain output signal
to wakeup an external device from an RTC alarm by setting the WU_DIR bit in the
RTCPMGT [1930h].
(1) I = Input, O = Output, Z = High impedance, S = Supply voltage, GND = Ground, A = Analog signal, BH = Bus Holder
(2) Input pins of type I, I/O, and I/O/Z are required to be driven at all times. To achieve the lowest power, these pins must not be allowed to
float. When they are configured as input or high-impedance state, and not driven to a known state, they may cause an excessive IO-
supply current. Prevent this current by externally terminating it or enabling IPD/IPU, if applicable.
(3) IPD = Internal pulldown, IPU = Internal pullup. For more detailed information on pullup/pulldown resistors and situations where external
pullup/pulldown resistors are required, see Section 3.8.1, Pullup/Pulldown Resistors.
(4) Specifies the operating I/O supply voltage for each signal
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