Deserial Serial Peripheral Interface (DSPI)
25-66
Freescale Semiconductor
PXR40 Microcontroller Reference Manual, Rev. 1
Figure 25-42. TX FIFO Pointers and Counter
25.5.4.1
Address Calculation for the First-in Entry and Last-in Entry in the TX
FIFO
The memory address of the first-in entry in the TX FIFO is computed by the following equation:
Eqn. 25-7
The memory address of the last-in entry in the TX FIFO is computed by the following equation:
Eqn. 25-8
TX FIFO Base - Base address of TX FIFO
TXCTR - TX FIFO Counter
TXNXTPTR - Transmit Next Pointer
TX FIFO Depth - Transmit FIFO depth, implementation specific
25.5.4.2
Address Calculation for the First-in Entry and Last-in Entry in the RX
FIFO
The memory address of the first-in entry in the RX FIFO is computed by the following equation:
Eqn. 25-9
The memory address of the last-in entry in the RX FIFO is computed by the following equation:
Eqn. 25-10
RX FIFO Base - Base address of RX FIFO
-
-
Entry A (first in)
Entry B
Entry C
Entry D (last in)
-
-
Push TX FIFO Register
Transmit Next
Data Pointer
Shift Register
SOUT
+1
-1
TX FIFO Counter
TX FIFO Base
First-in Entry Address
TX FIFO Base
4
TXNXTPTR
+
=
Last-in Entry address
TX FIFO Base
4
modulo TX FIFO depth
TXCTR
TXNXTPTR
1
–
+
+
=
First-in Entry Address
RX FIFO Base
4
POPNXTPTR
+
=
Last-in Entry address
RX FIFO Base
4
modulo RX FIFO depth
RXCTR
POPNXTPTR
1
–
+
+
=
Summary of Contents for PXR4030
Page 1: ...PXR40 Microcontroller Reference Manual Devices Supported PXR4030 PXR4040 PXR40RM Rev 1 06 2011...
Page 30: ...PXR40 Microcontroller Reference Manual Rev 1 Freescale Semiconductor xxx...
Page 40: ...PXR40 Microcontroller Reference Manual Rev 1 xl Freescale Semiconductor...
Page 66: ...Memory Map PXR40 Microcontroller Reference Manual Rev 1 2 4 Freescale Semiconductor...
Page 120: ...Signal Descriptions 3 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Page 860: ...FlexCAN Module 24 50 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Page 1167: ...Decimation Filter Freescale Semiconductor 28 53 PXR40 Microcontroller Reference Manual Rev 1...
Page 1168: ...Decimation Filter 28 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...