Toshiba TLCS-900/H1 Series Data Book page 111

3.6.5 Internal Boot-ROM Control
This section describes about built-in Boot-ROM.
For the specification of S/W in Boot-ROM, refer 3.20 Boot-ROM section.
(1) Boot-mode
Boot-mode is started by following AM1 and AM0 pins condition with reset.
(2) Boot-ROM memory map
Boot-ROM is consist of 8Kbyte-Masked ROM and assigned 3FE000H to 3FFFFFH address.
(3) Reset/Interrupt-Address conversion circuit
Originally, Reset/Interrupt Vector-area is assigned FFFF00H to FFFFEFH( (A)-area )
in TLCS-900/H1.
But because of Boot-ROM is assigned to another area, Reset/Interrupt-Vector-address conversion
circuit is prepared.
In Boot-mode, Reset/Interrupt Vector-area is assigned 3FFF00H to 3FFFEFH( (B)-area ) area
by it. And after Boot-sequence, its area can be changed to (A)-area by setting
BROMCR<VACE> to "0". So, (A)-area can be used only for aplication-system program.
This <VACE> is initialized to "1" in Boot-mode. At another starting mode, this-register
has no-meaning.
(note1) The last 16-byte area (FFFFF0H – FFFFFFH) is reserved for an emulator. So, this area
is not changed by <VACE>-register.
AM1 AM0
0 0
0 1
1 0
1 1
Start with BOOT(32-bit internal-MROM )
000000H
Internal-I/O,RAM
006000H
3FE000H
Internal-Boot-ROM
(8KB)
3FFF00H
400000H
FFFF00H
92CH21-107
Start mode
Don't use this setting
Start with 16-bit data bus
Start with 32-bit data bus
(B)Reset/Interrupt
Vector-area (256B)
(A)Reset/Interrupt
Vector-area (256B)
TMP92CH21