SC28L92 Philips Semiconductors, SC28L92 Datasheet - Page 23

• Manufacturer Part Number: SC28L92
• Description: 3.3V-5.0V Dual Universal Asynchronous Receiver/Transmitter DUART
• Manufacturer: Philips Semiconductors

In block error mode, block error conditions must be cleared by using the error reset command (command 4x) or a receiver reset.
Philips Semiconductors
For the receiver these bits control the number of FIFO positions
filled when the receiver will attempt to interrupt. After the reset the
receiver FIFO is empty. The default setting of these bits cause the
receiver to attempt to interrupt when it has one or more bytes in it.
MR0[5:4]—Tx interrupt fill level.
Table 4. Transmitter FIFO interrupt fill level
Table 4a. Transmitter FIFO interrupt fill
MR1A Mode Register 1
NOTE:
MR1A is accessed when the Channel A MR pointer points to MR1.
The pointer is set to MR1 by RESET or by a ‘set pointer’ command
applied via CR command 1. After reading or writing MR1A, the
pointer will point to MR2A.
MR1A[7]—Channel A Receiver Request-to-Send Control
(Flow Control)
This bit controls the deactivation of the RTSAN output (OP0) by the
receiver. This output is normally asserted by setting OPR[0] and
negated by resetting OPR[0]. Proper automatic operation of flow
control requires OPR[0] (channel A) or OPR[1] (channel B) to be set
to logical 1.
MR1A[7] = 1 causes RTSAN to be negated (OP0 is driven to a ‘1’
[V
This is the beginning of the reception of the ninth byte. If the FIFO is
not read before the start of the tenth or 17th byte, an overrun
condition will occur and the tenth or 17th or 17th byte will be lost.
However, the bit in OPR[0] is not reset and RTSAN will be asserted
again when an empty FIFO position is available. This feature can be
used for flow control to prevent overrun in the receiver by using the
RTSAN output signal to control the CTSN input of the transmitting
device.
2000 Jan 21
CC
3.3V–5.0V Dual Universal Asynchronous
Receiver/Transmitter (DUART)
MR0[5:4]
MR0[5:4]
0x00
0x08
MR1A/
MR1B
Addr
]) upon receipt of a valid start bit if the Channel A FIFO is full.
00
01
10
11
00
01
10
11
MR0(3) = 0 (8 bytes)
level MR0(3) = 1 (16 bytes)
Rx CONTROLS
0 = No
1 = Yes
BIT 7
RTS
1 or more bytes empty (Tx RDY)
1 or more bytes empty (Tx RDY)
16 bytes empty (Tx EMPTY)
8 bytes empty (Tx EMPTY)
12 or more bytes empty
4 or more bytes empty
6 or more bytes empty
8 or more bytes empty
Interrupt Condition
Interrupt Condition
0 = RxRDY
1 = FFULL
RxINT
BIT 6
BIT 1
ERROR
0 = Char
1 = Block
MODE
BIT 5
23
BIT 4
00 = With Parity
01 = Force Parity
10 = No Parity
11 = Multi-drop Mode
For the transmitter these bits control the number of FIFO positions
empty when the transmitter will attempt to interrupt. After the reset
the transmit FIFO has 8 bytes empty. It will then attempt to interrupt
as soon as the transmitter is enabled. The default setting of the MR0
bits (5:4) condition the transmitter to attempt to interrupt only when it
is completely empty. As soon as one byte is loaded, it is no longer
empty and hence will withdraw its interrupt request.
MR0[3]—Selects the FIFO depth at 8 or 16 bytes. See Tables 3 and 4
MR0[2:0]—These bits are used to select one of the six baud rate
groups.
See Table 5 for the group organization.
Other combinations of MR2[2:0] should not be used
Note: MR0[3:0] are not used in channel B and should be set to 0.
MR1[6]—Bit 1 of the receiver interrupt control. See description
under MR0[6].
MR1A[5]—Channel A Error Mode Select
This bit select the operating mode of the three FIFOed status bits
(FE, PE, received break) for Channel A. In the ‘character’ mode,
status is provided on a character-by-character basis; the status
applies only to the character at the top of the FIFO. In the ‘block’
mode, the status provided in the SR for these bits is the
accumulation (logical-OR) of the status for all characters coming to
the top of the FIFO since the last ‘reset error’ command for
Channel A was issued.
MR1A[4:3|—Channel A Parity Mode Select
If ‘with parity’ or ‘force parity’ is selected a parity bit is added to the
transmitted character and the receiver performs a parity check on
incoming data MR1A[4:3] = 11 selects Channel A to operate in the
special multi-drop mode described in the Operation section.
MR1A[2]—Channel A Parity Type Select
This bit selects the parity type (odd or even) if the ‘with parity’ mode
is programmed by MR1A[4:3], and the polarity of the forced parity bit
if the ‘force parity’ mode is programmed. It has no effect if the ‘no
PARITY MODE
000 Normal mode
001 Extended mode I
100 Extended mode II
BIT 3
PARITY TYPE
0 = Even
1 = Odd
BIT 2
BIT 1
Product specification
CHARACTER
SC28L92
BITS PER
00 = 5
01 = 6
10 = 7
11 = 8
BIT 0