MPC563XM Reference Manual, Rev. 1
Freescale Semiconductor
783
Preliminary—Subject to Change Without Notice
23.4.2.3.2
Parameter Addresses and Endianness
To access parameter number
xxx
, eTPU Microengine(s) would select address xxx. The Host would add
(xxx*4)
to the SPRAM base address to access the same parameter. For example, parameter 0x101 is seen
by the Host in
(SPRAM base a0x404)
. An example of SPRAM memory map is shown in
. The Host can access the SPRAM with a 32-bit-wide bus cycle to a four-byte aligned address,
16-bit-wide bus cycle to a two-byte aligned address, or 8-bit wide bus cycle to any byte address.
The address of the 24-bit parameters and the most significant byte depends on the endianness of the MCU.
For more details, see the
”.
23.4.2.3.3
Parameter Concurrency
Host accesses to parameters may occur in parallel with eTPU Microengine accesses. Readings taken from
a group of parameters while they are being simultaneously updated may lack coherency. eTPU provides
mechanisms to ensure parameter coherency in accesses from both Host side and Microengine side,
including the use of a coherent dual-parameter transfer mechanism, described in detail on
“Parameter Sharing and Coherency
.”
23.4.2.3.4
Parameter Sign Extension Area
The SPRAM address space to the Host is mirrored in a Parameter Sign Extension - PSE - area (see
”). Accesses from the Host to the PSE area differ from accesses to the
standard SPRAM address space as follows:
•
Writes
: the most significant byte of the parameters is not written, and the SPRAM retains the old
byte value, regardless of the Host access size.
•
Reads
: the most significant bit of the 24-bit parameter (that is, the msbit of the second most
significant 32-bit parameter byte) is repeated in the 8 most significant bits of the read value on all
32-bit reads and most significant 16- and 8-bit reads.
The same parameters written in the standard SPRAM address space are read from the PSE area with the
same offsets, and vice-versa. See
for a reference of the address offsets in big and little endian
machines.
This feature reliefs the Host from extending the signal of 24-bit eTPU parameters before calculations, and
from read-modify-write accesses to modify 24-bit parameters at the SPRAM.
23.4.2.4
SPRAM Organization
The SPRAM internal partition for channel allocation is dynamic and programmed in the Channel Registers
(see
Section 23.3.7.1, “ETPUCxCR - eTPU Channel x Configuration Register
).
The Host application is responsible for allocating a different parameter base address to each channel during
the initial eTPU configuration, and to allocate enough parameters for the selected Function, with no
unintentional overlapping between parameters of different functions.
Besides channel parameters, global areas may have to be allocated for parameters that are shared by more
than one channel, in one or both Engines. Also, temporary parameter areas should be reserved to be used
Содержание MPC5632M
Страница 22: ...MPC563XM Reference Manual Rev 1 22 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 62: ...MPC563XM Reference Manual Rev 1 62 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 92: ...MPC563XM Reference Manual Rev 1 92 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 168: ...MPC563XM Reference Manual Rev 1 168 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 242: ...MPC563XM Reference Manual Rev 1 242 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 302: ...MPC563XM Reference Manual Rev 1 302 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 410: ...MPC563XM Reference Manual Rev 1 410 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 440: ...MPC563XM Reference Manual Rev 1 440 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 464: ...MPC563XM Reference Manual Rev 1 464 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 554: ...MPC563XM Reference Manual Rev 1 554 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 590: ...MPC563XM Reference Manual Rev 1 590 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 622: ...MPC563XM Reference Manual Rev 1 622 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 716: ...MPC563XM Reference Manual Rev 1 716 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 1114: ...MPC563XM Reference Manual Rev 1 1114 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 1144: ...MPC563XM Reference Manual Rev 1 1144 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 1266: ...MPC563XM Reference Manual Rev 1 1266 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 1316: ...MPC563XM Reference Manual Rev 1 1316 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 1348: ...MPC563XM Reference Manual Rev 1 1348 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 1362: ...MPC563XM Reference Manual Rev 1 1362 Freescale Semiconductor Preliminary Subject to Change Without Notice ...
Страница 1382: ...MPC563XM Reference Manual Rev 1 1382 Freescale Semiconductor Preliminary Subject to Change Without Notice ...