Datasheet

PN532_C1 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2017. All rights reserved.
Product data sheet
COMPANY PUBLIC
Rev. 3.6 — 28 November 2017
115436 78 of 222
NXP Semiconductors
PN532/C1
Near Field Communication (NFC) controller
8.3.4.7 HSU_PRE register
This register is used to configure the baud rate generator prescaler.The prescaler
enlarges the range of the counter (at the cost of a lower resolution). The division factor of
the prescaler ranges from 1 (20) to 256 (28).
8.3.4.8 HSU_CNT register
This register is used to configure the baud rate generator counter.
Here is a table of recommendation for some data rates:
Table 115. HSU_PRE register (SFR: address ADh) bit allocation
Bit 7 6 5 4 3 2 1 0
Symbol hsu_prescaler[7:0]
Reset 00011000
Access R/W R/W R/W R/W R/W R/W R/W R/W
Table 116. Description of HSU_PRE bits
Bit Symbol Description
7 to 0 hsu_prescaler[7:0] In conjunction with HSU_CNT, defines the HSU baud rate.
Baud rate = f
clk
/ ((hsu_prescaler +1) * hsu_counter)
Table 117. HSU_CNT register (SFR: address AEh) bit allocation
Bit 7 6 5 4 3 2 1 0
Symbol hsu_counter[7:0]
Reset 01110000
Access R/W R/W R/W R/W R/W R/W R/W R/W
Table 118. Description of HSU_CNT bits
Bit Symbol Description
7 to 0 hsu_counter[7:0] In conjunction with HSU_PRE, defines the HSU baud rate.
Baud rate = f
clk
/ ((hsu_prescaler +1) * hsu_counter)
Table 119. Recommendation for HSU data rates
Targeted data
rate
HSU_CNT
value
HSU_PRE
value
Real HSU
freq
Min
recommended
Host HSU freq
Max
recommended
Host HSU freq
9 600 0x71 0x18 9 516 9 326 9 706
19 200 0x9D 0x08 19 193 18 810 19 576
38 400 0x65 0x06 38 359 37 592 39 126
57 600 0x9D 0x02 57 579 56 428 58 730
115 200 0xEB 0x00 115 404 113 096 117 712
230 400 0x76 0x00 229 831 225 234 234 427
460 800 0x3B 0x00 459 661 450 467 468 854
921 600 0x1D 0x00 935 172 916 468 953 875
1 288 000 0x15 0x00 1 291 429 1 265 600 1 317 257