SAF1761BE/V1,557 NXP Semiconductors, SAF1761BE/V1,557 Datasheet - Page 20

• Manufacturer Part Number: SAF1761BE/V1,557
• Manufacturer: NXP Semiconductors

Specifications of SAF1761BE/V1,557

• Lead Free Status / Rohs Status: Compliant

NXP Semiconductors
SAF1761_1
Product data sheet
7.3.2 PIO mode access, memory write cycle
7.3.3 PIO mode access, register read cycle
7.3.4 PIO mode access, register write cycle
7.3.5 DMA mode, read and write operations
The PIO memory writes access is similar to a normal memory access. It is not necessary
to set the pre-fetching address before a write cycle to the memory.
The SAF1761 internal write address will not be automatically incremented during
consecutive write accesses; unlike in a series of SAF1761 memory read cycles. The
memory write address must be incremented before every access.
The PIO register read access is similar to a general register access. It is not necessary to
set a pre-fetching address before a register read.
The SAF1761 register read address will not be automatically incremented during
consecutive read accesses; unlike in a series of SAF1761 memory read cycles. The
SAF1761 register read address must be correctly specified before every access.
The PIO register write access is similar to a general register access. It is not necessary to
set a pre-fetching address before a register write.
The SAF1761 register write address will not be automatically incremented during
consecutive write accesses; unlike in a series of SAF1761 memory read cycles. The
SAF1761 register write address must be correctly specified before every access.
The internal SAF1761 host controller DMA is a slave DMA. The host system processor or
DMA must ensure the data transfer to or from the SAF1761 memory.
The SAF1761 DMA supports a DMA burst length of 1, 4, 8 and 16 cycles for both the
16-bit and 32-bit data bus width. DREQ will be asserted at the beginning of the first burst
of a DMA transfer and will be de-asserted on the last cycle, RD_N or WR_N active pulse,
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The address written to the Memory register is incremented and used to successively
pre-fetch data from the memory irrespective of the value on the address bus for each
bank, until a new value for a bank is written to the Memory register. This is valid only
when the address refers to the memory space (400h to FFFFh).
For example, consider the following sequence of operations:
– Write the starting (read) address 4000h and bank1 = 01b to the Memory register.
– Write the starting (read) address 4100h and bank2 = 10b to the Memory register.
When RD_N is asserted for three cycles with A[17:16] = 01b, the returned data
corresponds to addresses 4000h, 4004h and 4008h.
Remark: Once 4000h is written to the Memory register for bank1, the bank select
value determines the successive incremental addresses used to fetch data. That
is, the fetching of data is independent of the address on A[15:0] lines.
When RD_N is asserted for four cycles with A[17:16] = 10b, the returned data
corresponds to addresses 4100h, 4104h, 4108h and 410Ch.
Consequently, the RD_N assertion with A[17:16] = 01b will return data from 400Ch
because the bank1 read stopped there in the previous cycle. Also, RD_N
assertions with A[17:16] = 10b will now return data from 4110h because the bank2
read stopped there in the previous cycle.
Rev. 01 — 18 November 2009
Hi-Speed USB OTG controller
SAF1761
© NXP B.V. 2009. All rights reserved.
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