CD2401 Intel, CD2401 Datasheet - Page 73

• Manufacturer Part Number: CD2401
• Description: Multi-protocol Communications Controller
• Manufacturer: Intel

6.2.5
Datasheet
Table 13. BREAK Sequencing
Table 14. SSPC[x] Settings
Note: In addition to insert delay, a ‘break’ can also be increased beyond one full character by transmitting
more than one ‘Send BREAK’ sequence at a time.
Special Characters Special Character Transmission
Selected special characters can be sent preemptively by setting the SndSpc bit (STCR[3]). The
CD2401 channel acknowledges the command by clearing the STCR. Along with the SndSpc bit,
the host needs to setup the three SSPC bits (STCR[2:0]) to select which character is to be sent.
When the host commands a special character transmission, the channel completes transmitting any
characters in the transmit shift and transmit holding registers, and then transmit the special
character sequence. Any other characters awaiting transmission in the FIFO or through DMA are
transmitted after the special character.
If the transmitter is off due to in-band flow control, the special characters override and are sent.
Special characters override out-of-band flow control. Also, if the transmitter is disabled, the special
character send command overrides and the character is sent.
00h–81h
00h–82h
xxh
00h–83h
00h–00h
SSPC2
Sequence
0
0
0
1
0
1
1
1
SSPC1
0
1
1
0
0
0
1
1
Send BREAK – Send a line break for at least one
character time.
Insert delay – To increase the break generation
beyond one character time, use the insert delay
sequence. The inserted delay is xx, where xx is a
binary number. The delay is xx times the ‘tick’ set
by the TPR. The minimum period of TPR should
be one millisecond. If the insert delay sequence is
not preceded by a Send BREAK sequence, there
is an inserted delay of all ‘1’s (high) on the output
for duration xx.
Stop BREAK – This must follow a Send BREAK
or Insert Delay sequence.
Send NUL – If the user needs to send a NULL
character and ETC is set to ‘1’, the user can
embed 00h–00h to send one NULL character. If
there are less than 8-bits per character, the user
can also send a NULL character by ‘sending’ 80h.
SSCP0
1
0
1
0
0
1
0
1
Send special character #1.
Send special character #2.
Send special character #3.
Send special character #4.
Reserved
Reserved
Reserved
Reserved
Function
Multi-Protocol Communications Controller — CD2401
Function
73