STM32W108HB STMicroelectronics, STM32W108HB Datasheet - Page 93

• Manufacturer Part Number: STM32W108HB
• Description: High-performance, IEEE 802.15.4 wireless system-on-chip with embedded Flash memory
• Manufacturer: STMicroelectronics

Specifications of STM32W108HB

• Receive Current (w/ Cpu): 27 mA
• Transmit Current (w/ Cpu, +3 Dbm Tx): 31 mA
• Low Deep Sleep Current, With Retained Ram And Gpio: 400 nA/800 nA with/without sleep timer
• Standard Arm Debug Capabilities: Flash patch & breakpoint; data watchpoint & trace; instrumentation trace macrocell
• Single Voltage Operation: 2.1-3.6 V with internal 1.8 V and 1.25 V regulators

STM32W108HB STM32W108CC STM32W108CB STM32W108CZ
9.6.4
9.6.5
9.7
DMA
The DMA Channels section describes how to configure and use the serial receive and
transmit DMA channels.
The receive DMA channel has special provisions to record UART receive errors. When the
DMA channel transfers a character from the receive FIFO to a buffer in memory, it checks
the stored parity and frame error status flags. When an error is flagged, the
SC1_RXERRA/B register is updated, marking the offset to the first received character with a
parity or frame error. Similarly if a receive overrun error occurs, the SC1_RXERRA/B
registers mark the error offset. The receive FIFO hardware generates the INT_SCRXOVF
interrupt and DMA status register indicates the error immediately, but in this case the error
offset is 4 characters ahead of the actual overflow at the input to the receive FIFO. Two
conditions will clear the error indication: setting the appropriate SC_RXDMARST bit in the
SC1_DMACTRL register, or loading the appropriate DMA buffer after it has unloaded.
Interrupts
UART interrupts are generated on the following events:
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To enable CPU interrupts, set the desired interrupt bits in the second level INT_SCxCFG
register, and enable the top level SCx interrupt in the NVIC by writing the INT_SCx bit in the
INT_CFGSET register.
Direct memory access (DMA) channels
The STM32W108 serial DMA channels enable efficient, high-speed operation of the SPI
and UART controllers by reducing the load on the CPU as well as decreasing the frequency
of interrupts that it must service. The transmit and receive DMA channels can transfer data
between the transmit and receive FIFOs and the DMA buffers in main memory as quickly as
it can be transmitted or received. Once software defines, configures, and activates the DMA,
it only needs to handle an interrupt when a transmit buffer has been emptied or a receive
buffer has been filled. The DMA channels each support two memory buffers, labeled A and
B, and can alternate ("ping-pong") between them automatically to allow continuous
communication without critical interrupt timing.
Transmit FIFO empty and last character shifted out (depending on SCx_INTMODE,
either the 0 to 1 transition or the high level of SC1_UARTTXIDLE)
Transmit FIFO changed from full to not full (depending on SCx_INTMODE, either the 0
to 1 transition or the high level of SC1_UARTTXFREE)
Receive FIFO changed from empty to not empty (depending on SCx_INTMODE, either
the 0 to 1 transition or the high level of SC1_UARTRXVAL)
Transmit DMA buffer A/B complete (1 to 0 transition of SC_TXACTA/B)
Receive DMA buffer A/B complete (1 to 0 transition of SC_RXACTA/B)
Character received with parity error
Character received with frame error
Character received and lost when receive FIFO was full (receive overrun error)
Doc ID 16252 Rev 13
Serial interfaces
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