ht82k75rew Holtek Semiconductor Inc., ht82k75rew Datasheet - Page 55

• Manufacturer Part Number: ht82k75rew
• Description: Ht82m75rew/ht82k75rew 2.4ghz Transceiver 8-bit Otp Mcu
• Manufacturer: Holtek Semiconductor Inc.

DC-DC Converter
There are two ways to supply power to the RF Trans-
ceiver. One is through the on-chip DC-DC converter and
the other is without the DC-DC converter. With DC-DC
converter, the RF Transceiver consumes lower current.
With the DC-DC converter, power pins including
VDD_RF1, VDD_RF2, VDD_D, VDD_A, VDD_PLL and
VDD_CP should be hardwired to the DC-DC converter
output, pin VDD_2V2 of the RF Transceiver. Without
DC-DC converter, all the power pins should be directly
hardwired to the external supplied voltage.
For this device the on-chip DC-DC converter is not
used. User can set LREG0x250 [4] to 0 and
LREG0x273 to 0x4E to bypass the DC-DC converter.
When the DC-DC converter is bypassed, pins
VDD_2V2 and VDD_3V are shorted internally.
Battery Monitor
The RF Transceiver provides a function to monitor the
RF Transceiver supplied voltage. A 4-bit voltage thresh-
old can be configured so that when the supplied voltage
is lower than the threshold, the system will be notified.
For battery monitor function, please refer to the Section
named Battery Monitor Operations.
Power Saving Modes
The RF Transceiver power modes are classified into the
following four modes:
Rev. 1.00
IDLE: RF circuit off. The regulator, oscillator, and digi-
tal circuits are on.
STANDBY: RF/MAC/BB shutdown with sleep and
32MHz clocks remain active
DEEP_SLEEP: All power is shutdown except the
power to the digital circuits and registers and FIFOs
data are retained.
Block Diagram of Voltage Regulators with DC-DC Converter On/Bypass
55
IDLE mode is rarely used because the device should at
least always turns on its RX circuit to capture the on-air
RF signals. The only difference between STANDBY
mode and DEEP_SLEEP mode is the power status of
the sleep clock. To wake the RF Transceiver up, the
MCU host has to control the time of sleep process.
The power management control is used for the low
power operation of MAC and baseband modules. It
manages to turn on and off the 32 MHz clock when the
RF Transceiver goes into power saving mode. By turn-
ing off the 32 MHz clock, the MAC and baseband circuits
become inactive regardless whether their power sup-
plies exist or not. All the digital modules are clock-gated
automatically. That means only when a module is func-
tioning, its clock would then be turned on. This approach
efficiently decreases certain amount of the current con-
sumption.
RF Transceiver Interfacing Block
The interfacing block mainly includes three parts named
SPI interface, GPIO and Interrupt signal. Each of them
is described as followings.
SPI Interface
The MCU communicates with the RF Transceiver via an
internal SPI interface to read/write the control registers
and FIFOs. The SPI interface connected to the MCU
SPI master in the RF Transceiver has the following fea-
tures:
POWER_DOWN: All power is shutdown. Registers
and FIFOs data are not retained, a wake-up input sig-
nal can wake up the RF Transceiver.
A 4-line slave SPI interface composed of: SEN (SPI
enable), SCLK (SPI Clock), SI (Serial Data Input) and
SO (Serial Data Output).
Most significant bit (MSB) of all addresses and data
transfers on the SPI interface is done first.
HT82M75REW/HT82K75REW
June 11, 2010