User's Manual l TQMLS10xxA UM 0105 l © 2022, TQ-Systems GmbH
Page 16
4.11
RTC
An RTC type PCF85063A is assembled. RTC signal CLKOUT (32 kHz) is routed to the TQMLS10xxA connector (X2-118).
RTC signal INT# can be used in several ways:
•
External use: Signal is accessible at the TQMLS10xxA connector, Pull-Up to 3.3 V on the TQMLS10xxA.
•
The signal is also available on the Board Controller for wake-up.
TQMLS10xxA connector
3.3 V
LDO
5.0 V
VBAT
CLKOUT
Board
Controller
LS CPU
RTC
I²C Bus
32 kHz
Level
Shifter
3.3
V →
1.8 V
RTC_INT
_OUT#
CPU_RTC
CLKOUT
INT#
Figure 14: Block diagram RTC interface
The RTC has I
2
C address
The RTC is clocked with a 32.768 kHz crystal with an accuracy of ±20 ppm at +25 °C. This equals to a maximum deviation
of 1.7 seconds per day. The accuracy at +85 °C is ±30 ppm. This equals to a maximum deviation of 2.6 seconds per day.
The RTC is supplied by VBAT. A GoldCap
®
or a battery is required.
Figure 15: Block diagram RTC buffering interface
4.12
UART
It is recommended to assemble 4.7 kΩ Pull-Ups at the UART_SOUT signals on the carrier board.
For details contact
