Random-Number-Generator Registers - Texas Instruments CC253x User Manual

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Note that the LFSR must be properly seeded by writing to RNDL before the CRC calculations start.
Usually, the seed value for CRC calculations should be 0x0000 or 0xFFFF.

14.3 Random-Number-Generator Registers

This section describes the random-number-generator registers.
RNDL (0xBC) – Random-Number-Generator Data, Low Byte
Bit Name Reset
7:0 RNDL[7:0] 0xFF
RNDH (0xBD) – Random-Number-Generator Data, High Byte
Bit Name Reset
7:0 0xFF
RNDH[7:0]
ADCCON1 (0xB4) – ADC Control 1 (see also
Bit Name Reset
7:4 – 0011
3:2 RCTRL[1:0] 00
1:0 – 11
SWRU191F – April 2009 – Revised April 2014
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R/W Description
R/W Random value, random seed, or CRC result, low byte
When used for random-number generation, writing to this register twice seeds the random-
number generator. Writing to this register copies the 8 LSBs of the LFSR to the 8 MSBs and
replaces the 8 LSBs with the data value written.
The value returned when reading from this register is the 8 LSBs of the LFSR.
When used for random-number generation, reading this register returns the 8 LSBs of the
random number. When used for CRC calculations, reading this register returns the 8 LSBs of the
CRC result.
R/W Description
R/W Random value, CRC result, or input data, high byte
When written, a CRC16 calculation is triggered, and the data value written is processed starting
with the MSB.
The value returned when reading from this register is the 8 MSBs of the LFSR.
When used for random-number generation, reading this register returns the 8 MSBs of the
random number. When used for CRC calculations, reading this register returns the 8 MSBs of the
CRC result.
Section 12.2.10)
R/W Description
– For CC2533, these bits are reserved. For the other devices, see the ADCCON1 (0xB4) –
ADC Control 1 description in
R/W Controls the 16-bit random-number generator
automatically returns to 00 when the operation has completed.
00: Normal operation. (13× unrolling)
01: Clock the LFSR once (13× unrolling)
10: Reserved
11: Stopped. Random-number generator is turned off.
R/W Reserved. Always set to 11
Copyright © 2009–2014, Texas Instruments Incorporated
Random-Number-Generator Registers
Section 12.2.10.
(Chapter 14). When 01 is written, the setting
Random-Number Generator
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