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gateware.spi: shorten counters

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This commit is contained in:
Robert Jördens 2016-02-29 01:51:33 +01:00
parent a4504905bd
commit 9a1d6a51a4
1 changed files with 18 additions and 13 deletions
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31
artiq/gateware/spi.py
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@ -226,16 +226,18 @@ class SPIMaster(Module):
(1, 1): idle high, output on falling, input on rising
1 lsb_first: LSB is the first bit on the wire (reset=0)
1 half_duplex: 3-wire SPI, in/out on mosi (reset=0)
12 div_write: counter load value to divide this module's clock
to the SPI write clk. clk pulses are asymmetric
if the value is odd, favoring longer setup over hold times.
f_clk/f_spi_write == div_write + 2 (reset=0)
12 div_read: ditto for the read clock
8 undefined
8 div_write: counter load value to divide this module's clock
to the SPI write clk.
f_clk/f_spi_write == 2*(div_write + 1) (reset=0)
8 div_read: ditto for the read clock
xfer (address 1):
16 cs: active high bit mask of chip selects to assert
8 write_len: 0-M bits
8 read_len: 0-M bits
6 write_len: 0-M bits
2 undefined
6 read_len: 0-M bits
2 undefined
data (address 0):
M write/read data
@ -257,16 +259,19 @@ class SPIMaster(Module):
("clk_phase", 1),
("lsb_first", 1),
("half_duplex", 1),
("div_write", 12),
("div_read", 12),
("padding", 8),
("div_write", 8),
("div_read", 8),
])
config.offline.reset = 1
assert len(config) <= len(bus.dat_w)
xfer = Record([
("cs", 16),
("write_length", 8),
("read_length", 8),
("write_length", 6),
("padding0", 2),
("read_length", 6),
("padding1", 2),
])
assert len(xfer) <= len(bus.dat_w)
@ -355,11 +360,11 @@ SPI_DATA_ADDR, SPI_XFER_ADDR, SPI_CONFIG_ADDR = range(3)
def SPI_DIV_WRITE(i):
return i << 8
return i << 16
def SPI_DIV_READ(i):
return i << 20
return i << 24
def SPI_CS(i):