Added PMGR description

README.md

@@ -1,12 +1,22 @@
 # macintosh-portable
+
+## Introduction
+
 This is an attempt to reverse-engineer **Macintosh Portable** motherboard's power distribution and management subsystem.
 
 * The files can be opened and edited using [KiCad](http://www.kicad-pcb.org/).
 * Check out the [PDF releases](https://github.com/ppieczul/macintosh-portable/releases) of the schematics.
 * You may take a look at my collection of vintage computers: [oldcrap.org](https://oldcrap.org)
 
-Pictures of the **V1M hybrid** board with marked components:
+## V1M Hybrid Board
 
 ![front](pictures/macintosh-portable-v1m-front.jpeg)
 ![resistors](pictures/macintosh-portable-v1m-resistors.jpeg)
 ![back](pictures/macintosh-portable-v1m-back.jpeg)
+
+## Apple Power Manager Chip (PMGR)
+
+This is [Mitsubishi M50753](http://www.bitsavers.org/components/mitsubishi/_dataBooks/1989_Mitsubishi_Single-Chip_8-Bit_Microcomputers.pdf) Microcontroller with embedded EPROM.
+
+![M50753-pinout](pictures/macintosh-portable-PMGR-M50753-pinout.png)
+![M50753-pins](pictures/macintosh-portable-PMGR-M50753-pin-description.png)