SC16C754B NXP Semiconductors, SC16C754B Datasheet - Page 24

• 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
7.3 FIFO Control Register (FCR)
This is a write-only register that is used for enabling the FIFOs, clearing the FIFOs, setting
transmitter and receiver trigger levels, and selecting the type of DMA signalling.
shows FIFO control register bit settings.
Table 11.
Bit
7:6
5:4
3
2
1
0
Symbol
FCR[7] (MSB),
FCR[6] (LSB)
FCR[5] (MSB),
FCR[4] (LSB)
FCR[3]
FCR[2]
FCR[1]
FCR[0]
FIFO control register bits description
5 V, 3.3 V and 2.5 V quad UART, 5 Mbit/s (max.) with 64-byte FIFOs
Rev. 04 — 6 October 2008
Description
RX trigger. Sets the trigger level for the RX FIFO.
00 — 8 characters
01 — 16 characters
10 — 56 characters
11 — 60 characters
TX trigger. Sets the trigger level for the TX FIFO.
00 — 8 spaces
01 — 16 spaces
10 — 32 spaces
11 — 56 spaces
FCR[5:4] can only be modified and enabled when EFR[4] is set. This is
because the transmit trigger level is regarded as an enhanced function.
DMA mode select.
Reset TX FIFO.
Reset RX FIFO.
FIFO enable.
logic 0 = set DMA mode 0
logic 1 = set DMA mode 1
logic 0 = no FIFO transmit reset (normal default condition)
logic 1 = clears the contents of the transmit FIFO and resets the FIFO
counter logic (the transmit shift register is not cleared or altered). This
bit will return to a logic 0 after clearing the FIFO.
logic 0 = no FIFO receive reset (normal default condition)
logic 1 = clears the contents of the receive FIFO and resets the FIFO
counter logic (the receive shift register is not cleared or altered). This
bit will return to a logic 0 after clearing the FIFO.
logic 0 = disable the transmit and receive FIFO (normal default
condition)
logic 1 = enable the transmit and receive FIFO
SC16C754B
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Table 11
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