71M6541D Maxim, 71M6541D Datasheet - Page 82

• Manufacturer Part Number: 71M6541D
• Description: The 71M6541D/71M6541F/71M6541G/71M6542F/71M6542G are Teridian™ 4th-generation single-phase metering SoCs with a 5MHz 8051-compatible MPU core, low-power RTC with digital temperature compensation, flash memory, and LCD driver
• Manufacturer: Maxim

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The MPU has access to a variety of registers that signal the event that caused the wake up. See
Wake Up Behavior
Table 67
71M6541D/F/G and 71M6542F/G Data Sheet
Transitions from both LCD and SLP mode to BRN mode can be initiated by the following events:
•
CE (Computation Engine)
FIR
ADC, VREF
PLL
Battery Measurement
Temperature sensor
Max MPU clock rate
MPU_DIV clk. divider
ICE
DIO Pins
Watchdog Timer
LCD
LCD Boost
EEPROM Interface (2-wire)
EEPROM Interface (3-wire)
UART (full speed)
Optical TX modulation
Flash Read
Flash Page Erase
Flash Write
RAM Read and Write
Wakeup Timer
OSC and RTC
DRAM data preservation
NV RAM data preservation
Notes:
82
Circuit Function
Wake-up timer timeout.
Pushbutton (PB) is activated.
A rising edge on SEGDIO4, SEGDIO52 (71M6542F/G only) or SEGDIO55.
Activity on the RX or OPT_RX pins.
1.
2.
3.
The CE is active in BRN mode, but ADC data is inaccurate. The MPU should halt the CE to conserve power (CE_E = 0,
I/O RAM 0x2106[0]).
“--“ indicates that the corresponding circuit is not active
“Boost” implies that the LCD boost circuit is active (i.e., LCD_VMODE[1:0] = 10 (I/O RAM 0x2401[7:6]). The LCD boost
circuit requires a clock from the PLL to function. Thus, the PLL is automatically kept active if LCD boost is active while in
LCD mode, otherwise the PLL is de-activated.
shows the circuit functions available in each operating mode.
for details.
PLL_FAST=1
(from PLL)
4.92MHz
38.4kHz
MSN (Mission Mode)
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
System Power
Table 67: Available Circuit Functions
PLL_FAST=0
(from PLL)
1.57MHz
38.9kHz
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
PLL_FAST=1
(from PLL)
BRN (Brownout Mode)
4.92MHz
38.4kHz
Note 1
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
--
--
Battery Power
PLL_FAST=0
(from PLL)
1.57MHz
38.9kHz
Note 1
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
--
--
Boost
LCD
Yes
Yes
Yes
Yes
Yes
Yes
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
2
2
3.4
SLEEP
Rev 2
Yes
Yes
Yes
Yes
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--