sc16c652 NXP Semiconductors, sc16c652 Datasheet - Page 12

• Manufacturer Part Number: sc16c652
• Description: Dual Uart With 32 Bytes Of Transmit And Receive Fifos
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 11634
Product data
6.10 Loop-back mode
6.9 DMA operation
Table 6:
The SC16C652 FIFO trigger level provides additional flexibility to the user for block
mode operation. The user can optionally operate the transmit and receive FIFOs in
the DMA mode (FCR[3]). The DMA mode affects the state of the RXRDY and TXRDY
output pins. Tables
Table 7:
Table 8:
The internal loop-back capability allows on-board diagnostics. In the loop-back mode,
the normal modem interface pins are disconnected and reconfigured for loop-back
internally (see
diagnostic testing. In the loop-back mode, the transmitter output (TX) and the receiver
input (RX) are disconnected from their associated interface pins, and instead are
connected together internally. The CTS, DSR, CD, and RI are disconnected from
Output
baud rate
50
75
110
150
300
600
1200
2400
3600
4800
7200
9600
19.2 k
38.4 k
57.6 k
115.2 k
Non-DMA mode
1 = FIFO empty
0 = at least 1 byte in FIFO
Non-DMA mode
1 = at least 1 byte in FIFO
0 = FIFO empty
Baud rate generator programming table using a 1.8432 MHz clock
Effect of DMA mode on state of RXRDY pin
Effect of DMA mode on state of TXRDY pin
Figure
Output
16 clock divisor
(decimal)
2304
1536
1047
768
384
192
96
48
32
24
16
12
6
3
2
1
Rev. 04 — 20 June 2003
7
and
4). MCR[0-3] register bits are used for controlling loop-back
8
Dual UART with 32 bytes of transmit and receive FIFOs
show this.
Output
16 clock divisor
(HEX)
900
600
417
300
180
C0
60
30
20
18
10
0C
06
03
02
01
DMA mode
0-to-1 transition when FIFO empties
1-to-0 transition when FIFO reaches trigger level,
or time-out occurs
DMA mode
0-to-1 transition when FIFO becomes full
1-to-0 transition when FIFO goes below trigger level
DLM
program value
(HEX)
09
06
04
03
01
00
00
00
00
00
00
00
00
00
00
00
© Koninklijke Philips Electronics N.V. 2003. All rights reserved.
SC16C652
DLL
program value
(HEX)
00
00
17
00
80
C0
60
30
20
18
10
0C
06
03
02
01
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