SW00ENB-ZCC Toshiba, SW00ENB-ZCC Datasheet - Page 375

• Manufacturer Part Number: SW00ENB-ZCC
• Description: MCU, MPU & DSP Development Tools CASEWORKS
• Manufacturer: Toshiba

Specifications of SW00ENB-ZCC

• Tool Type: Development Software Support
• Core Architecture: 870
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

(0xFFFF_E510)
3.3.6
SEQMOD
DSU-ICE Interface
used for software debugging using an external DSU-ICE unit. In DSU mode, Port A serves as an
interface to the DSU-ICE, and can not be used as general-purpose port, INT1–INT4 or Serial Bus
Interface (SBI) pins. Consult the DSU-ICE operation manual for a description of debugging using the
DSU-ICE. When the TMP1940FDBF is in DSU mode, the on-chip flash memory provides a security
feature.
(1) Flash security feature
(2) Securing the flash (Disabling debugging with a DSU-ICE)
(3) Unsecuring the flash (Enabling debugging with a DSU-ICE)
If P37 is sampled low at the rising edge of
Name
Read/Write
Reset Value
Function
Note: This register must be read as a 32-bit quantity. Bits 1 to 31 are read as 0s.
The TMP1940FDBF supports on-board debugging while it is installed on a printed circuit board.
The TMP1940FDBF provides a security feature to prevent intrusive access to the flash memory.
When the flash memory is in the secure state, a DSU-ICE is denied access to the entirety of the
flash memory.
Once program debug is completed, set the FSE bit in the Flash Control/Status (FLCS) register (see
section 3.6.14) and write the Auto Security On command. This turns on the flash security feature.
While the flash memory is in the secure state, a DSU-ICE can not read its contents. When the chip
is powered off and powered on again, the SEQON bit in the SEQMOD register is automatically
set, which disables debugging using a DSU-ICE until the flash memory is unsecured.
The flash memory may only be unsecured by clearing the SEQON bit in the SEQMOD register
and then writing a special code (0x0000_00C5) to the Security Control (SEQCNT) register. This
prevents runaway software from inadvertently turning off the security feature. Unsecuring the
flash memory enables the DSU interface. The flash memory can be secured again by setting the
SEQON bit in the SEQMOD and writing 0x0000_00C5 to the SEQCNT while the chip is
powered.
7
6
TMP1940FDBF-17
5
RESET
4
, the TMP1940FDBF enters DSU mode, which is
3
2
TMP1940FDBF
1
1: Security on
0: Security off
SEQON
R/W
0
1