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Broken, but partly ready for 608

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This commit is contained in:
Peter D. Gray 2019-07-16 10:54:19 -04:00
parent 755e02f513
commit cd98dc4680
1 changed files with 19 additions and 9 deletions
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28
misc/obsolete-code/secel.py
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@ -1,13 +1,14 @@
#
# Secure Element
#
# Talk to the ATECC508A, which drives the Genuine/Caution LED's and holds secrets.
# Talk to the ATECC[56]08A, which drives the Genuine/Caution LED's and holds secrets.
#
# - connected to "onewire" on PA0
# - not a standard "onewire" interface at all
# - full datasheet is under NDA (unfortunately, bad policy)
# - but very simmilar to ATSHA204 and family chips
# - bootloader can also read/write to this chip
# - XXX presently broken.
#
from machine import Pin, UART
from time import sleep_us, sleep_ms
@ -46,12 +47,12 @@ class OP:
ECDH = 0x43
GenDig = 0x15
GenKey = 0x40
HMAC = 0x11
HMAC = 0x11 # 508a only
Info = 0x30
Lock = 0x17
MAC = 0x08
Nonce = 0x16
Pause = 0x01
Pause = 0x01 # 508a only
PrivWrite = 0x46
Random = 0x1B
Read = 0x02
@ -60,6 +61,10 @@ class OP:
UpdateExtra = 0x20
Verify = 0x45
Write = 0x12
OP_AES = 0x51 # 608a only
OP_KDF = 0x56 # 608a only
OP_SecureBoot = 0x80 # 608a only
OP_SelftTest = 0x77 # 608a only
# most errors are really communications failures
ERROR_CODES = {
@ -329,9 +334,13 @@ class SecureElement:
pkt = self.serialize(pkt)
ow = self.ow
# must start with wakeup sequence
ow.write(b'\x00') # WAKEUP token
ow.read() # thow out old garbage
sleep_us(2500) # tWHI: 2.5ms min
# send cmd packet
ow.write(pkt)
sleep_us(40) # tTURNAROUND (80)
@ -349,11 +358,12 @@ class SecureElement:
while 1:
# read back response
ow.write(b'\x00') # WAKEUP token
while ow.any():
ow.read(1) # thow out old garbage
sleep_us(2500) # tWHI: 2.5ms min
ow.write(self.x88)
if 0:
ow.write(b'\x00') # WAKEUP token
while ow.any():
ow.read(1) # thow out old garbage
sleep_us(2500) # tWHI: 2.5ms min
ow.write(self.x88)
# expect back
# - the TX token (echo)
@ -379,7 +389,7 @@ class SecureElement:
# probably an error response
raise ChipErrorResponse(hex(resp[1]))
#print("wr len: %r" % resp)
print("wrong len: %s" % b2a_hex(resp))
raise WrongResponseLength(len(resp))
# check CRC, over all but last two bytes.