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ST STM32F103 series Reference Manual

ST STM32F103 series
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DocID13902 Rev 15 1050/1128
RM0008 Ethernet (ETH): media access control (MAC) with DMA controller
1064
Ethernet DMA transmit poll demand register (ETH_DMATPDR)
Address offset: 0x1004
Reset value: 0x0000 0000
This register is used by the application to instruct the DMA to poll the transmit descriptor list.
The transmit poll demand register enables the Transmit DMA to check whether or not the
current descriptor is owned by DMA. The Transmit Poll Demand command is given to wake
up the TxDMA if it is in Suspend mode. The TxDMA can go into Suspend mode due to an
underflow error in a transmitted frame or due to the unavailability of descriptors owned by
transmit DMA. You can issue this command anytime and the TxDMA resets it once it starts
re-fetching the current descriptor from host memory.
EHERNET DMA receive poll demand register (ETH_DMARPDR)
Address offset: 0x1008
Reset value: 0x0000 0000
This register is used by the application to instruct the DMA to poll the receive descriptor list.
The Receive poll demand register enables the receive DMA to check for new descriptors.
This command is given to wake up the RxDMA from Suspend state. The RxDMA can go into
Suspend state only due to the unavailability of descriptors owned by it.
Bits 6:2 DSL: Descriptor skip length
This bit specifies the number of words to skip between two unchained descriptors. The
address skipping starts from the end of current descriptor to the start of next descriptor.
When DSL value equals zero, the descriptor table is taken as contiguous by the DMA, in
Ring mode.
Bit 1 DA: DMA Arbitration
0: Round-robin with Rx:Tx priority given in bits [15:14]
1: Rx has priority over Tx
Bit 0 SR: Software reset
When this bit is set, the MAC DMA controller resets all MAC Subsystem internal registers
and logic. It is cleared automatically after the reset operation has completed in all of the core
clock domains. Read a 0 value in this bit before re-programming any register of the core.
313029282726252423222120191817161514131211109876543210
TPD
rw_wt
Bits 31:0 TPD: Transmit poll demand
When these bits are written with any value, the DMA reads the current descriptor pointed to
by the ETH_DMACHTDR register. If that descriptor is not available (owned by Host),
transmission returns to the Suspend state and ETH_DMASR register bit 2 is asserted. If the
descriptor is available, transmission resumes.
313029282726252423222120191817161514131211109876543210
RPD
rw_wt

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ST STM32F103 series Specifications

General IconGeneral
BrandST
ModelSTM32F103 series
CategoryMicrocontrollers
LanguageEnglish

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