avr_isp: add dump to test https://github.com/sigrokproject/libsigrokdecode/pull/113

avr_isp/atmega48/README.txt

@@ -0,0 +1,39 @@
+-------------------------------------------------------------------------------
+AVR ISP / Atmel ATmega48
+-------------------------------------------------------------------------------
+
+This is an example capture of the AVR in-system programming (ISP) protocol.
+
+The device used for ISP was a ESP32-S2 containing code to progam the target using ISP.
+
+The target was a board with an Atmel ATmega48 chip.
+
+The capture contains the serial programming instructions:
+  - Programming enable
+  - Chip erase
+  - Poll RDY/nBSY
+  - Load program memory page, high byte
+  - Load program memory page, low byte
+  - Read signature byte
+  - Read program memory, low byte
+  - Read lock bits
+  - Read fuse bits
+  - Read fuse high bits
+  - Read extended fuse bits
+  - Read calibration byte
+  - Write program memory page
+  - Write fuse bits
+  - Write fuse high bits
+  - Write extended fuse bits
+
+Logic analyzer setup
+--------------------
+
+The logic analyzer used was a Cypress FX2 development board (at 2MHz):
+
+  Probe       AVR ISP header
+  -------------------------
+  0 (black)   SCK
+  1 (brown)   MISO
+  2 (red)     MOSI
+  3 (orange)  CS