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Enhanced Time Processing Unit (eTPU2)
MPC5644A Microcontroller Reference Manual, Rev. 6
930
Freescale Semiconductor
24.5.9.1
SPRAM microoperations
The access to SPRAM is made by providing an address and a register to perform a data transfer, except
semaphore operations, which are also classified in the SPRAM group. Only P and DIOB registers can
exchange data with SPRAM. Microengine always addresses SPRAM in 32-bit boundaries, for 8, 24, or
32-bit wide data.
Direction is determined by the field RW in all addressing modes: RW = 0 selects read and RW = 1 selects
write.
24.5.9.1.1
SPRAM Addressing Modes
The eTPU has four addressing modes:
•
Absolute
•
Selected Channel Relative
•
Indirect
•
Engine Relative
The addressing modes Absolute and Selected Channel Relative use immediate bits to form the physical
address of SPRAM, which is identified in microinstruction as a field called AID. AID field can be 3, 7, or
8-bit wide depending on the addressing mode.
Absolute addressing mode
In Absolute addressing mode, the address range is 256 parameters, addressed by field AID, which in this
mode is 8-bit wide. These parameters are located in SPRAM addresses from 0 to 255.
physical_address = AID[7:0]
Selected channel relative addressing mode
In Selected Channel Relative addressing mode, only the first 8 (with 3-bit AID) or 128 (with 7-bit AID)
parameters of the selected channel are accessible, depending on the microinstruction format. Physical
address is calculated using the channel parameter base address that is specified in field CPBA of
ETPU_CxCR (see
Section 24.4.7.1, ETPU_CxCR – eTPU Channel x Configuration Register
is added to channel parameter base address to compose the physical address. The equation is:
physical_address = selected_channel_parameter_base_a AID[6:0], or
physical_address = selected_channel_parameter_base_a AID[2:0]
Indirect addressing mode
In Indirect Addressing mode the physical address is taken from DIOB register. Only DIOB bits 13 to 2 are
relevant. Since the SPRAM word address is shifted two bits up in DIOB, its contents hold the same
parameter address value used by Host. The equation is:
physical_address = DIOB[13:2], or
physical_address = (truncated) DIOB / 4
Summary of Contents for MPC5644A
Page 2: ...MPC5644A Microcontroller Reference Manual Rev 6 2 Freescale Semiconductor...
Page 24: ...MPC5644A Microcontroller Reference Manual Rev 6 24 Freescale Semiconductor...
Page 26: ...MPC5644A Microcontroller Reference Manual Rev 6 26 Freescale Semiconductor...
Page 52: ...Introduction MPC5644A Microcontroller Reference Manual Rev 6 52 Freescale Semiconductor...
Page 56: ...Memory Map MPC5644A Microcontroller Reference Manual Rev 6 56 Freescale Semiconductor...
Page 1228: ...Decimation Filter MPC5644A Microcontroller Reference Manual Rev 6 1228 Freescale Semiconductor...
Page 1440: ...FlexCAN Module MPC5644A Microcontroller Reference Manual Rev 6 1440 Freescale Semiconductor...