diff --git a/docs/_docs/design-250-prom-specific-code.md b/docs/_docs/design-250-prom-specific-code.md
index a286fc2..249ee0c 100644
--- a/docs/_docs/design-250-prom-specific-code.md
+++ b/docs/_docs/design-250-prom-specific-code.md
@@ -37,10 +37,11 @@ different chip technologies.
 |AT29C010  |Atmel        |Flash  |28C    |Only with 128 byte or less sector size|
 |SST39SF040|Microchip    |Flash  |SST39SF|All SST39SF0x0 supported|
 |SST28SF040|SST          |Flash  |SST28SF|All SST28SF0x0 supported|
-|M27C256   |ST Micro     |EPROM  |       |VCC=6.5V, VPP=12.75V to pgm|
+|M27C256   |ST Micro     |EPROM  |27     |VCC=6.5V, VPP=12.75V to pgm|
 |W27C257   |Winbond      |EEPROM |27     |Continuous 12V or 14V for program/erase|
 |SST27SF020|SST          |Flash  |27     |12V continuous for pgm/erase|
 |8755A     |Intel        |EPROM  |8755A  |Requires 25V pulses to program|
+|2316      |Commodore    |ROM    |23     |Read-only|
 
 
 # PromDevice Modules
@@ -109,6 +110,29 @@ Chips that use high voltage pulses for each byte are not supported.  For those c
 elements of the [8755A hardware](8755A-hardware) may be leveraged to build a version of
 the programmer that is able to provide high voltage pulses.
 
+## PromDevice23
+
+The PromDevice23 driver is used to read Commodore 2316, 2332, and 2364 mask-programmed ROMs.
+This were used in early computers like the Commodore PET, Atari, and others.
+
+Most ROM chips can be read using the standard 28C driver.  The 23 series ROMs are unique because
+the chip select polarity is configurable when the chip is initally programmed.  This means that, for example, 
+some chips will use CS1 as an active HIGH signal and other will use it active LOW.  This existing
+Unlock command was repurposed in this driver to scan the chip to determine the polarity of the
+Chip Select pin(s).
+
+For the 2316 make the following connections:
+
+* CS3 to Arduino A0 (WE)
+* CS2 to Arduino A1 (CE)
+* CS1 to Arduino A2 (OE)
+
+The 2332 does not have a CS3, and the 2364 does not have CS3 or CS2, so those Arduino pins are not used.
+
+Before reading the chip, run the Unlock command to scan the Chip Selects.  This will try all combinations
+of CS values to read data from the chip.  After the Unlock command runs successfully, the Dump or Read commands
+can then be used to read from the chip.
+
 ## PromDevice8755
 
 TommyPROM has a driver for Intel 8755 EPROMs.  This driver replaces the 28C driver at
diff --git a/docs/_docs/ref-300-2316-2332-roms.md b/docs/_docs/ref-300-2316-2332-roms.md
new file mode 100644
index 0000000..c9fd7a9
--- /dev/null
+++ b/docs/_docs/ref-300-2316-2332-roms.md
@@ -0,0 +1,14 @@
+---
+title: PROM Types
+permalink: /docs/2316-roms
+exerpt: "2316, 2332, and 2364 Read Only Memory"
+---
+
+## 2316, 2332, and 2364 Mask-Programmable Read-only Memory
+
+|Model     |Type |CS3  |CS2  |CS1  |Notes|
+|:---      |:--- |:---:|:---:|:---:|:--- |
+|12345     |2316 | x   | H   | H   | |
+|12345     |2316 | x   | H   | H   | |
+| Commodore 64  |||
+|12345     |2332 | -   | H   | H   | |