sle44xx: extend the README for the SLE4442 captures

Create a README in the sle44xx/ parent directory, discuss the chip
family's features, and reference the Siemens datasheet. Extend the
README for the SLE4442 captures, don't assume that all users are
familiar with the chips and their protocol. The example dumps also
serve for learning and exploration of the curious. Fixup the probe
names (according to --show their names are in the 0..7 range).

1 files changed, 29 insertions, 0 deletions

diff --git a/sle44xx/README b/sle44xx/README
new file mode 100644
index 0000000..cd60134
--- /dev/null
+++ b/sle44xx/README
@@ -0,0 +1,29 @@
+------------------------------------------------------------------------
+Siemens SLE44xx Chip Card Protocol
+------------------------------------------------------------------------
+
+SLE 4418/4428/4432/4442 memory cards implement a 2-wire protocol for data
+communication (signals CLK and I/O). A RST signal can be used to terminate
+currently pending long memory reads, and resets the card's address counter
+when combined with CLK. The next response data then is the Answer to Reset
+(ATR) which identifies the chip's capabilities, and allows to adjust for
+subsequent communication of more requests.
+
+See the Siemens document for details:
+
+  ICs for Chip Cards
+  Intelligent 256-Byte EEPROM
+  SLE 4432/SLE 4442
+  Data Sheet 07.95
+
+
+Logic analyzer setup
+--------------------
+
+  Probe    SLE44xx
+  ----------------
+  0        I/O
+  1        CLK
+  2        RST
+
+See subdirectories for chip specific example files.