Product data

MFRC631 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2014. All rights reserved.
Product data sheet
COMPANY PUBLIC
Rev. 3.3 — 4 February 2014
227433 92 of 120
NXP Semiconductors
MFRC631
High performance ISO/IEC 14443 A/B reader solution
9.13 Clock configuration
9.13.1 SerialSpeed
This register allows to set speed of the RS232 interface. The default speed is set to
9,6kbit/s. The transmission speed of the interface can be changed by modifying the
entries for BR_T0 and BR_T1. The transfer speed can be calculated by using the
following formulas:
BR_T0 = 0: transfer speed = 27.12 MHz / (BR_T1 + 1)
BR_T0 > 0: transfer speed = 27.12 MHz / (BR_T1 + 33) / 2^(BR_T0  1)
The framing is implemented with 1 startbit, 8 databits and 1 stop bit. A parity bit is not
used. Transfer speeds above 1228,8 kbit/s are not supported.
Table 159. Effect of gain and highpass corner register settings
rcv_gain
(Hex.)
rcv_hpcf
(Hex.)
fl (kHz) fU (MHz) gain (dB20) bandwith
(MHz)
03 00 38 2,3 60 2,3
03 01 79 2,4 59 2,3
03 02 150 2,6 58 2,5
03 03 264 2,9 55 2,6
02 00 41 2,3 51 2,3
02 01 83 2,4 50 2,3
02 02 157 2,6 49 2,4
02 03 272 3,0 41 2,7
01 00 42 2,6 43 2,6
01 01 84 2,7 42 2,6
01 02 157 2,9 41 2,7
01 03 273 3,3 39 3,0
00 00 43 2,6 35 2,6
00 01 85 2,7 34 2,6
00 02 159 2,9 33 2,7
00 03 276 3,4 30 3,1
Table 160. SerialSpeed register (address3Bh); reset value: 7Ah
Bit 7 6 5 4 3 2 1 0
Symbol BR_T0 BR_T1
Access
rights
r/w r/w
Table 161. SerialSpeed bits
Bit Symbol Description
7 to 5 BR_T0 BR_T0 = 0: transfer speed = 27.12 MHz / (BR_T1 + 1)
BR_T0 > 0: transfer speed = 27.12 MHz / (BR_T1 + 33) / 2^(BR_T0  1)
4 to 0 BR_T1 BR_T0 = 0: transfer speed = 27.12 MHz / (BR_T1 + 1)
BR_T0 > 0: transfer speed = 27.12 MHz / (BR_T1 + 33) / 2^(BR_T0  1)