diff options
| -rw-r--r-- | decoders/lpc/lpc.py | 37 |
1 files changed, 31 insertions, 6 deletions
diff --git a/decoders/lpc/lpc.py b/decoders/lpc/lpc.py index 42b7353..9bc91cd 100644 --- a/decoders/lpc/lpc.py +++ b/decoders/lpc/lpc.py @@ -27,7 +27,8 @@ ANN_ASCII = 0 # ... fields = { - 'START': { # LAD[3:0] values that are not listed are reserved. + # START field (indicates start or stop of a transaction) + 'START': { 0b0000: 'Start of cycle for a target', 0b0001: 'Reserved', 0b0010: 'Grant for bus master 0', @@ -43,18 +44,42 @@ fields = { 0b1100: 'Reserved', 0b1101: 'Start of cycle for a Firmware Memory Read cycle', 0b1110: 'Start of cycle for a Firmware Memory Write cycle', - 0b1111: 'Stop/Abort (end of a cycle for a target)', + 0b1111: 'Stop/abort (end of a cycle for a target)', }, - 'CT_DR': { # Bit 0 (LAD[0]) is unused. + # Cycle type / direction field + # Bit 0 (LAD[0]) is unused, should always be 0. + # Neither host nor peripheral are allowed to drive 0b11x0. + 'CT_DR': { 0b0000: 'I/O read', 0b0010: 'I/O write', 0b0100: 'Memory read', 0b0110: 'Memory write', 0b1000: 'DMA read', 0b1010: 'DMA write', - 0b1100: 'Reserved', - 0b1110: 'Reserved', + 0b1100: 'Reserved / not allowed', + 0b1110: 'Reserved / not allowed', + }, + # SIZE field (determines how many bytes are to be transferred) + # Bits[3:2] are reserved, must be driven to 0b00. + # Neither host nor peripheral are allowed to drive 0b0010. + 'SIZE': { + 0b0000: '8 bits (1 byte)', + 0b0001: '16 bits (2 bytes)', + 0b0010: 'Reserved / not allowed', + 0b0011: '32 bits (4 bytes)', + }, + # CHANNEL field (bits[2:0] contain the DMA channel number) + 'CHANNEL': { + 0b0000: '0', + 0b0001: '1', + 0b0010: '2', + 0b0011: '3', + 0b0100: '4', + 0b0101: '5', + 0b0110: '6', + 0b0111: '7', }, + # SYNC field (used to add wait states) 'SYNC': { 0b0000: 'Ready', 0b0001: 'Reserved', @@ -294,7 +319,7 @@ class Decoder(srd.Decoder): ## continue # Store LAD[3:0] bit values (one nibble) in local variables. - # Most (but not all states needs this). + # Most (but not all) states need this. if self.state != 'IDLE': lad = (lad3 << 3) | (lad2 << 2) | (lad1 << 1) | lad0 lad_bits = bin(lad)[2:] |