Texas Instruments CC253x User Manual

www.ti.com Random-Number-Generator Registers
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 R/W Description
7:0
RNDL[7:0]
0xFF R/W Random value/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.
RNDH (0xBD) – Random-Number-Generator Data, High Byte
Bit Name Reset R/W Description
7:0
RNDH[7:0]
0xFF R/W Random value or CRC result/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.
ADCCON1 (0xB4) – ADC Control 1 (see also Section 12.2.10)
Bit Name Reset R/W Description
7:4 – 0011 - For CC2533, these bits are reserved. For the other devices, see the ADCCON1 (0xB4) –
ADC Control 1 description in Section 12.2.10.
3:2
RCTRL[1:0]
00 R/W Controls the 16-bit random-number generator (Chapter 14). When 01 is written, the setting
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.
1:0 – 11 R/W Reserved. Always set to 11
151
SWRU191C–April 2009–Revised January 2012 Random-Number Generator
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Texas Instruments CC253x Specifications

General

Brand	Texas Instruments
Model	CC253x
Category	Microcontrollers
Language	English