SC16C754B NXP Semiconductors, SC16C754B Datasheet - Page 17

• Manufacturer Part Number: SC16C754B
• Description: 5 V - 3.3 V and 2.5 V quad UART - 5 Mbit/s (max.)
• Manufacturer: NXP Semiconductors

NXP Semiconductors
SC16C754B_4
Product data sheet
6.6.1.1 Transmitter
6.6.1.2 Receiver
6.6.1 Single DMA transfers (DMA mode 0/FIFO disable)
6.6 DMA operation
There are two modes of DMA operation, DMA mode 0 or DMA mode 1, selected by
FCR[3].
In DMA mode 0 or FIFO disable (FCR[0] = 0) DMA occurs in single character transfers. In
DMA mode 1, multi-character (or block) DMA transfers are managed to relieve the
processor for longer periods of time.
Figure 11
When empty, the TXRDY signal becomes active. TXRDY will go inactive after one
character has been loaded into it.
RXRDY is active when there is at least one character in the FIFO. It becomes inactive
when the receiver is empty.
Fig 11. TXRDY and RXRDY in DMA mode 0/FIFO disable
wrptr
wrptr
shows TXRDY and RXRDY in DMA mode 0/FIFO disable.
FIFO EMPTY
5 V, 3.3 V and 2.5 V quad UART, 5 Mbit/s (max.) with 64-byte FIFOs
TX
Rev. 04 — 6 October 2008
TXRDY
TXRDY
location filled
at least one
rdptr
rdptr
FIFO EMPTY
RX
SC16C754B
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© NXP B.V. 2008. All rights reserved.
RXRDY
location filled
RXRDY
at least one
002aaa232
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