Dma Register Description - ST STM32F40 Series Reference Manual

Ethernet (ETH): media access control (MAC) with DMA controller
Bit 1 TSTTR: Time stamp target time reached
Bit 0 TSSO: Time stamp second overflow
Ethernet PTP PPS control register (ETH_PTPPPSCR)
Address offset: 0x072C
Reset value: 0x0000 0000
This register controls the frequency of the PPS output.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
Bits 31:4 Reserved, must be kept at reset value.
Bits 3:0 PPSFREQ: PPS frequency selection
Note: If digital rollover is used (TSSSR=1, bit 9 in ETH_PTPTSCR), it is recommended not to
29.8.4

DMA register description

This section defines the bits for each DMA register. Non-32 bit accesses are allowed as long
as the address is word-aligned.
Ethernet DMA bus mode register (ETH_DMABMR)
Address offset: 0x1000
Reset value: 0x0000 2101
The bus mode register establishes the bus operating modes for the DMA.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
Reserved
rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw
1003/1422
When set, this bit indicates that the value of the system time is greater than or equal to the
value specified in the Target time high and low registers
When set, this bit indicates that the second value of the time stamp has overflowed beyond
0xFFFF FFFF.
The PPS output frequency is set to 2
0000: 1 Hz with a pulse width of 125 ms for binary rollover and, of 100 ms for digital rollover
0001: 2 Hz with 50% duty cycle for binary rollover (digital rollover not recommended)
0010: 4 Hz with 50% duty cycle for binary rollover (digital rollover not recommended)
0011: 8 Hz with 50% duty cycle for binary rollover (digital rollover not recommended)
0100: 16 Hz with 50% duty cycle for binary rollover (digital rollover not recommended)
...
1111: 32768 Hz with 50% duty cycle for binary rollover (digital rollover not recommended)
use the PPS output with a frequency other than 1 Hz. Otherwise, with digital rollover,
the PPS output has irregular waveforms at higher frequencies (though its average
frequency will always be correct during any one-second window).
RDP
Doc ID 018909 Rev 4
Reserved
PPSFREQ
Hz.
PM
9 8 7 6 5
9 8 7 6 5
PBL DSL
rw rw rw rw rw rw
RM0090
4 3 2 1 0
ro ro
4 3 2 1 0
rs