ST STM32F101xx Reference Manual page 910

Ethernet (ETH): media access control (MAC) with DMA controller
Ethernet DMA receive descriptor list address register (ETH_DMARDLAR)
Address offset: 0x100C
Reset value: 0x0000 0000
The Receive descriptor list address register points to the start of the receive descriptor list.
The descriptor lists reside in the STM32F107xx's physical memory space and must be
word-aligned. The DMA internally converts it to bus-width aligned address by making the
corresponding LS bits low. Writing to the ETH_DMARDLAR register is permitted only when
reception is stopped. When stopped, the ETH_DMARDLAR register must be written to
before the receive Start command is given.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw
Bits 31:0 SRL: Start of receive list
This field contains the base address of the first descriptor in the receive descriptor list. The
LSB bits [1/2/3:0] for 32/64/128-bit bus width) are internally ignored and taken as all-zero by
the DMA. Hence these LSB bits are read only.
Ethernet DMA transmit descriptor list address register (ETH_DMATDLAR)
Address offset: 0x1010
Reset value: 0x0000 0000
The Transmit descriptor list address register points to the start of the transmit descriptor list.
The descriptor lists reside in the STM32F107xx's physical memory space and must be
word-aligned. The DMA internally converts it to bus-width-aligned address by taking the
corresponding LSB to low. Writing to the ETH_DMATDLAR register is permitted only when
transmission has stopped. Once transmission has stopped, the ETH_DMATDLAR register
can be written before the transmission Start command is given.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw
Bits 31:0 STL: Start of transmit list
This field contains the base address of the first descriptor in the transmit descriptor list. The
LSB bits [1/2/3:0] for 32/64/128-bit bus width) are internally ignored and taken as all-zero by
the DMA. Hence these LSB bits are read-only.
910/959
SRL
STL
9 8 7 6 5 4 3
9 8 7 6 5 4 3
RM0034
2 1 0
2 1 0