Bluetooth Audio Module
6.2. Reset
The module may be reset from several sources: RESETB pin, power-on reset, a UART break
character or via software configured watchdog timer.
The RESETB pin is an active low RESETB and is internally filtered using the internal low
frequency clock oscillator. A RESETB will be performed between 1.5 and 4.0ms following
RESETB being active. It is recommended that RESETB be applied for a period greater than
5ms.
At RESETB the digital I/O pins are set to inputs for bi-directional pins and outputs are tri-state.
The pull-down state is shown below.
Pin Name / Group
USB_DP
Pin Status on RESETB
N/a
N/a
PD
PU
PD
PD
PU
PD
PU
PD
PD
PD
PD
PD
USB_DN
UART_RX
UART_TX
SPI_MOSI
SPI_CLK
SPI_CSB
SPI_MISO
RESETB
PIOs
PCM_IN
PCM_CLK
PCM_SYNC
PCM_OUT
Table 9: Pin Status on Reset
6.3. PIO
EH-MB05 has a total of 11 digital programmable I/O terminals. They are powered from VDD
(3.3V). Their functions depend on firmware running on the device. PIO lines can be configured
through software to have either weak or strong pull-ups or pull-downs.
Note:
All PIO lines are configured as inputs with weak pull-downs at reset.
Any of the PIO lines can be configured as interrupt request lines or as wake-up lines from sleep
modes.
6.4. AIO
EH-MB05 has 2 analogue I/O terminals. Their functions depend on software. Typically ADC
functions can be configured to battery voltage measurement. They can also be used as a digital
PIO.
Shanghai Ehong Technologies Inc
