Table 68: available circuit functions, Table 67 – Rainbow Electronics 71M6542G User Manual

Page 82

v1.1

Transitions from both LCD and SLP mode to BRN mode can be initiated by the following events:
• Wake-up timer timeout.
• Pushbutton (PB) is activated.
• A rising edge on SEGDIO4, SEGDIO52 (71M6542F only) or SEGDIO55.
• Activity on the RX or OPT_RX pins.

The MPU has access to a variety of registers that signal the event that caused the wake up. See

3.4

Wake Up Behavior

for details.

Table 67

shows the circuit functions available in each operating mode.

Table 67: Available Circuit Functions

Circuit Function

System Power

Battery Power

MSN (Mission Mode)

BRN (Brownout Mode)

LCD

SLEEP

PLL_FAST=1 PLL_FAST=0 PLL_FAST=1 PLL_FAST=0

CE (Computation Engine)

Yes

Note 1

FIR

Yes

ADC, VREF

Yes

PLL

Yes

Boost

Battery Measurement

Yes

Temperature sensor

Yes

Max MPU clock rate

4.92MHz

(from PLL)

1.57MHz

(from PLL)

4.92MHz

(from PLL)

1.57MHz

(from PLL)

MPU_DIV clk. divider

Yes

ICE

Yes

DIO Pins

Yes

Watchdog Timer

Yes

LCD

Yes

LCD Boost

Yes

EEPROM Interface (2-wire)

Yes

EEPROM Interface (3-wire)

Yes

UART (full speed)

Yes

Optical TX modulation

38.4kHz

38.9kHz

38.4kHz

38.9kHz

Flash Read

Yes

Flash Page Erase

Yes

Flash Write

Yes

RAM Read and Write

Yes

Wakeup Timer

Yes

OSC and RTC

Yes

DRAM data preservation

Yes

NV RAM data preservation

Yes

Notes:

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.