MSC8144E Reference Manual, Rev. 3
26-64
Freescale
Semiconductor
Security Engine (SEC)
Cellular automata shift register (CASR)
Clock controller
Six ring oscillators
The states of the LFSR and CASR are advanced at unknown frequencies determined by the two
ring oscillator clocks and the clock control. When a read is performed, the oscillator clocks are
halted and a collection of bits from the LFSR and CASR are XORed together to obtain the 64-bit
random output.
In typical operation, the RNG is used through channel-controlled access, which means that most
reads and writes of RNG registers are directed by the SEC channels. Driver software would
perform core processor-controlled register accesses only on a few registers for initial
configuration and error handling.
The following subsections include general descriptions of the RNG registers and structures.
Section 26.5, Programming Model, on page 26-66 provides a detailed description of each
register and associated register fields.
26.4.7.1 RNG Mode Register
The RNG Mode Register is a writable location but all mode bits are currently reserved. It is
documented for the sake of consistency with the other EUs.
26.4.7.2 RNG Data Size Register
The RNG Data Size Register is used to tell the RNG to begin generating random data. The actual
contents of the Data Size Register do not affect the operation of the RNG. After a reset and prior
to the first write of data size, the RNG builds entropy without pushing data onto the FIFO. Once
the Data Size Register is written, the RNG will begin pushing data onto the FIFO. Data is pushed
onto the FIFO every 256 cycles until the FIFO is full. The RNG then attempts to keep the FIFO
full.
26.4.7.3 RNG Reset Control Register
This register contains three reset options specific to the RNG.
26.4.7.4 RNG Status Register
This RNG Status Register contains six fields that reflect the state of the RNG internal signals.
The RNG Status Register is read-only. Writing to this location results in an address error being
reflected in the RNG Interrupt Status Register.
26.4.7.5 RNG Interrupt Status Register
The Interrupt Status Register indicates which unmasked errors have occurred and have generated
error interrupts to the channel. Each bit in this register can only be set if the corresponding bit of
Summary of Contents for MSC8144E
Page 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Page 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
Page 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Page 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Page 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Page 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Page 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Page 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
Page 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...