From 2a640b1eb17f6ae39b6eef1de5796a711ac43239 Mon Sep 17 00:00:00 2001
From: kazblox <kazbloxmc@gmail.com>
Date: Wed, 28 Oct 2015 19:13:50 -0400
Subject: [PATCH] dpcplus: minor non-code related changes

-add missing copyright holders
-improve notes
-confirm ARM7 type
---
 src/devices/bus/vcs/dpcplus.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/src/devices/bus/vcs/dpcplus.c b/src/devices/bus/vcs/dpcplus.c
index 16d72f1c316..55abae7d05b 100644
--- a/src/devices/bus/vcs/dpcplus.c
+++ b/src/devices/bus/vcs/dpcplus.c
@@ -1,26 +1,34 @@
 // license:BSD-3-Clause
-// copyright-holders:
+// copyright-holders:David Haywood
 /***************************************************************************
 
 Atari 2600 cart with DPC+
 
-the DPC+ adds an ARM CPU amongst other things (display improvements, etc.)
+the DPC+ adds an ARM CPU, including video improvements plus an extra synthesizer.
 
-map (according to a blogpost on atariage):
-	NOTE: All banks are accessible via $F000
+Some info on the DPC+ hardware can be found on Darrell Spice Jr's guides:
+http://atariage.com/forums/blog/148/entry-11811-dpcarm-part-6-dpc-cartridge-layout/
+http://atariage.com/forums/blog/148/entry-11883-dpcarm-part-7-6507arm-exchange-of-information/
+http://atariage.com/forums/blog/148/entry-11903-dpcarm-part-8-multiple-functions/
+http://atariage.com/forums/blog/148/entry-11935-dpcarm-part-9-functional-menu/
+http://atariage.com/forums/blog/148/entry-11964-dpcarm-part-10-score-timer-display/
+http://atariage.com/forums/blog/148/entry-11988-dpcarm-part-12-gamepad-support/
+
+map:
+	Bankswitching uses addresses $FFF6-$FFFB
 
 	* ARM RAM mapped at $40000000 in this area
 	$0000-$0BFF: DPC+ driver (not accessible by 2600 itself)
-	$0C00-$1BFF: Bank 0
+	$0C00-$1BFF: Bank 0 - ARM code starts here, but 6507 code can also be placed here aswell
 	$1C00-$2BFF: Bank 1
 	$2C00-$3BFF: Bank 2
 	$3C00-$4BFF: Bank 3
 	$4C00-$5BFF: Bank 4
-	$5C00-$6BFF: Bank 5
+	$5C00-$6BFF: Bank 5 - 6507 code
 	* ARM RAM mapped at $40000C00 in this area
 	$6C00-$7BFF: Display Data (indirect access)
 	* ARM RAM mapped at $40001C00 in this area
-	$7C00-$7FFF: Frequency Data (not accessible by 2600 itself)
+	$7C00-$7FFF: Synth Frequency Data (not accessible by 2600 itself)
 
 ***************************************************************************/
 
@@ -72,12 +80,12 @@ WRITE32_MEMBER(a26_rom_dpcplus_device::armrom_w)
 
 static ADDRESS_MAP_START( dpcplus_arm7_map, AS_PROGRAM, 32, a26_rom_dpcplus_device )
 	// todo: implement all this correctly
-	AM_RANGE(0x00000000, 0x00007fff) AM_READWRITE(armrom_r,armrom_w)// flash, 32k
+	AM_RANGE(0x00000000, 0x00007fff) AM_READWRITE(armrom_r,armrom_w) // flash, 32k
 	AM_RANGE(0x40000000, 0x40001fff) AM_RAM // sram, 8k
 ADDRESS_MAP_END
 
 static MACHINE_CONFIG_FRAGMENT( a26_dpcplus )
-	MCFG_CPU_ADD("arm", ARM7, 70000000)    // correct type?
+	MCFG_CPU_ADD("arm", ARM7, 70000000)
 	MCFG_CPU_PROGRAM_MAP(dpcplus_arm7_map)
 MACHINE_CONFIG_END