Freescale Semiconductor MPC8260 - Manual (Page 815)

Serial Management Controllers (SMCs)
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 27-3
Table 27-1 describes SMCMR fields.
Bit 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Field: UART — CLEN SL PEN PM — SM DM TEN REN
Transparent — BS REVD
GCI ME — C#
Reset 0000_0000_0000_0000
R/W R/W
Addr 0x0x11A82 (SMCMR1), 0x0x11A92 (SMCMR2)
Figure 27-2. SMC Mode Registers (SMCMR1/SMCMR2)
Table 27-1. SMCMR1/SMCMR2 Field Descriptions
Bits Name Description
0 — Reserved, should be cleared
1–4 CLEN Character length (UART). Number of bits in the character minus one. The total is the sum of 1 (start
bit always present) + number of data bits (5–14) + number of parity bits (0 or 1) + number of stop
bits (1 or 2). For example, for 8 data bits, no parity, and 1 stop bit, the total number of bits in the
character is 1 + 8 + 0 + 1 = 10. So, CLEN should be programmed to 9.
Characters range from 5–14 bits. If the data bit length is less than 8, the msbs of each byte in
memory are not used on transmit and are written with zeros on receive. If the length is more than 8,
the msbs of each 16-bit word are not used on transmit and are written with zeros on receive.
The character must not exceed 16 bits. For a 14-bit data length, set SL to one stop bit and disable
parity. For a 13-bit data length with parity enabled, set SL to one stop bit. Writing values 0 to 3 to
CLEN causes erratic behavior.
Character length (transparent). The values 3–15 specify 4–16 bits per character. If a character is
less than 8 bits, the most-significant bits of the byte in buffer memory are not used on transmit and
are written with zeros on receive. If character length is more than 8 bits but less than 16, the
most-significant bits of the half-word in buffer memory are not used on transmit and are written with
zeros on receive.
Note: Using values 0–2 causes erratic behavior. Larger character lengths increase an SMC
channel’s potential performance and lowers the performance impact of other channels. For
instance, using 16- rather than 8-bit characters is encouraged if 16-bit characters are acceptable in
the end application.
Character length (GCI). Number of bits in the C/I and monitor channels of the SCIT channels 0 or
1. (values 0–15 correspond to 1–16 bits) CLEN should be 13 for SCIT channel 0 or GCI (8 data bits,
plus A and E bits, plus 4 C/I bits = 14 bits). It should be 15 for the SCIT channel 1 (8 data, bits, plus
A and E bits, plus 6 C/I bits = 16 bits).
5 SL Stop length. (UART)
0 One stop bit.
1 Two stop bits.
— Reserved, should be cleared. (transparent)
ME Monitor enable. (GCI)
0 The SMC does not support the monitor channel.
1 The SMC supports the monitor channel.